We begin with a story thats breaking hearts tonight. A busload of students, their bus exploding in a crash. And splitsecond decisions were made that meant life or death. Bazi kanani on the scene. Oh, my god. A bus and a truck. Reporter the deadly crash, towering flames and a black billowing funnel of smoke. Just saw a very, very large explosion and fireball. Reporter engulfing the tour bus, turning the side of the Northern California freeway into a makeshift triage area. Helicopters airlifting victims to nearby hospitals. This was a horrific collision. The impact was heard throughout the community. I went outside, everything was in flames already. There was a couple of explosions after that. Reporter 44 High School Seniors off to visit humboldt university. All of them part of a special program for low income students, many the first in their families to attend college. This is a very sad day for us. We promise to do everything we can for the students and families. Reporter the bus left los angeles before dawn for the 12hour trip north to humboldt. As the miles slipped by, the teens watched movies, listened to music. Then, suddenly, about four hours from their destination, a fedex tractor trailer swerved violently across the median, harley didnt see it coming. He was doing homework. I look up. The bus driver slams on the brakes. This loud screeching noise, ill never forget it. And then, within a split second, boom. The fedex truck was on fire. I pushed open the window. Got pushed down. Fell, scraped my arms, hands, knees. And someone fell on top of me. I was very lost and scared. And i cant even explain. I was very confused. I didnt believe, you never think this is going to happen to you. Reporter and shortly after we spoke, an emotional reunion. Harley, reunited with his parents. One family together tonight. Relief for this family, but heart break for so many other. Ten People Killed in the crash, including five students. Investigators are still trying to determine the cause. Officials saying those students were the ones who did all the right things, and their dreams are taken away. And now, we move to the indian ocean and the new energy in the search for the black boxes and that missing passenger plane. Abcs Clayton Sandell shows us the perils three miles down at the bottom of the ocean. Reporter two dozen ships and planes today, searching the indian ocean from above. Amid growing confidence about what lies below. We have very much narrowed down the search area and we are very confident that the signals that we are detecting are from the black box on mh370. Reporter but those signals havent been heard since tuesday and without them, no way to home in. So teams will soon turn to using this sonar scanner to begin looking for wreckage. Its slow going. How long would it take . Its probably a month and a half to two months of effort. Reporter it takes that long . Yes, it does. Reporter the sea floor here rests under 15,000 feet of water, a remote, pitch black alien landscape of plains and mountains 12,000 feet high. When or if malaysia 370s boxes are found, a sub like this will bring them up. It will go down and actually comb through the field and find what the investigators need to help find the cause of the crash. It is a mystery of clues hidden at the bottom of a vast ocean, that may take years to solve. Clayton sandell, abc news, perth, australia. And here at home, tax day is fast approaching. And a sneak peek at the obama familys tax returns. The obamas reporting 481,000, a drop from 2012. 21 down. Over 600,000. The big drop is because sales of the president s books are down. And we decided to check on the irs service for taxpayer help. If you have a question about your tax return, can you get help . Heres abcs david kerley. Reporter the government wants your tax dollars. But if you call in with a question how to fill out specific forms. Reporter good luck getting an answer. We estimate your wait time to be between 30 and 60 minutes. The hold times are frustrating. You listen to pretty much the same song, for a really long time. You get hung up on. Reporter its so bad, recently the head of the irs went on youtube with a warning. There will frequently be extensive wait times. Reporter so we went to the irs commissioner with a simple question. How do you expect taxpayers to pay when they cant get an answer as to how much theyre supposed to pay . Thats our biggest concern. Reporter last year, there were 109 million calls to the irs. 40 of those calls trying to reach an agent went unanswered. Those who got through, average wait time, 18 minutes. Your advocate inside the agency has never seen service so bad. Im outraged. I feel that taxpayers have a right to quality service. Some might ask, why dont you reallocate funds so you can serve the taxpayer better . We have reallocated every dollar we can to serving the tax payer better. But we have obligations we cant avoid. Reporter the commissioner says the agency has cut 10,000 employees the past four years, because its budget was cut by 1 billion. This tax season, he hopes only 30 of all calls are unanswered. Thats a huge failure rate. I view it as intolerable and as i say, nobody cares more about it than the people that work for us. Reporter what can you do . Try the irs website, buy a tax software program, or go to a voluntary tax assistance office. Because all the head of the irs can offer is i apologize. David kerley, abc news, washington. On the case. And one more note out of washington. One last glitch for the outgoing secretary of health and human services, catherine sebelius. Who launched the calamitous Government Health care website. During her farewell speech. Knowing they can take care of themselves and their families. Unfortunately, a page is missing. So im just grateful for having had this wonderful opportunity. Oh, well. The president has nominated his budget chief has her replacement. And pope francis, making headlines tonight. With a very unusual off the cuff remark about the Sexual Abuse Scandal in the catholic church. Asking the victims to forgive, saying you dont play around with the lives of children, taking personal responsibility. Begging forgiveness. And after three days of grilling by the prosecutor they call the bull terrier, Oscar Pistorius is still on the stand. The prosecutor trying to make the tale he told seem preposterous. Lama hasan was there. Reporter the grueling day three cross examination of Oscar Pistorius reaching a crescendo. You shot at her knowing that shes behind that door. Thats not true, my lady. Reporter the prosecutor nicknamed the bull terrier once again going after the paralympian accused of murdering his model girlfriend, reeva steenkamp. Asking if pistorius really was afraid of intruders the night he fired four bullets into a bathroom door, why he approached the bathroom at all. Why did you not leave through your bedroom door . My lady, i have very, very limited mobility on my stumps on a hard surface like tiles. Reporter or make sure steenkamp heard the warning pistorius says he made to get down and call police. You never waited for a response. Thats correct. Reporter with reeva in the bathroom cubicle and pistorius on the other side of this door, the prosecution today pouncing. Asking him how could he have not known she was in here . All week pistorius tested emotionally. And cross examination isnt even done yet. He has pled not guilty to all charges. Lama hasan, abc news, pretoria, south africa. So we turn to dan abrams. Three weeks into the trial, how is he doing . Based on everything weve seen so far, hes got to be worried. I cant see how the judge isnt going to convict him of at least the lesser crime of culpable homicide. And a lot of evidence against him with the gun charges. Hes got to be worried. So far, what is his biggest problem . Hes saying he didnt realize that reeva wasnt in the bed. But he had to get the gun from underneath the bed. The Biggest Issue for him is, where was he when this all started . He said he woke up, went to the balcony. Heard a noise in the bathroom, and realized someone was in there. He said, i concede, i didnt go in the balcony. This is important to evaluate, did he really believe that was an intruder there, or was it a fight . A really big change in testimony. Some three weeks possibly to go, right . Thanks. And last week, we reported on those caring for americas wounded warriors. Today, Michelle Obama and others linked arms to highlight new initiatives to help the families. Including one from the defense department. The burden that these women and men bear for our country is real. And they shouldnt have to shoulder it alone. The third anniversary of the white house initiative, joining forces. Next here tonight, the church and its secrets. A megawedding and 2,000 couples. The First American cameras to record this phenomenon and the men and women behind it. When were back in two minutes. Cameras to record this phenomenon and the men and women behind it. When were back in two minutes. When jake and i first set out on we ate anything. But in time you realize the better you eat, the better you feel. These days we both eat smarter. And i give jake purina cat chow naturals. Made with real chicken and salmon, its high in protein like a cats natural diet. And no added artificial flavors. Weve come a long way. And whatevers ahead, well be there for each other. Naturally. Purina cat chow naturals. Tonight, for the first time, american cameras take you inside a secretive religion. Next tonight, for the first time, american cameras take you inside a secretive religion. Three decades ago, we heard about a wedding of 2,000 couples in new york city. In Madison Square garden. Introducing a lot of us to the church of reverend moon. Tonight, juju chang is here with rare access and she found that this happened recently again. Reporter imagine a wedding with 2,000 couples, some who barely know each other. Thats whats happening at this stadium outside seoul, south korea. All are members of the unification church, founded by the late reverend sun myung moon, a self proclaimed messiah. Two years after his death, we were surprised to find his followers taking part in the phenomenon that earned the church so much attention in its heyday. The movement holds these weddings once a year. It says it has 3 million members worldwide, but critics say the number may be closer to 100,000. Many of these brides and grooms are the children of the original followers, taking their turn at the altar after being matched through a church database. Among them, glenn and his fiancee judilee. She is an aspiring artist, who flew from canada to meet glenn, a frontman for an indie band. They had never before laid eyes on each other. How do you explain that concept to the outside world, that i let my parents help me pick my mate . Sometimes i feel a little bit selfconscious. But i feel its not just marrying two people, its like marrying two families. Reporter both glenn and judilees parents were matched by reverend moon, his core belief, that multicultural unions would eliminate racial strife and usher in world peace. And in korea, we caught up with them moments before the wedding. How do you feel . Kind of like, surreal. Reporter as couples line up, the most important guest is arriving. True mother, reverend moons widow. She leads the elaborate ceremony. The exchange of rings for all 2,000 couples. Definitely felt like our moment. Even though were in a sea of brides and grooms, i felt like it was our moment. Reporter as they make their way out as married couples, most will sleep apart for 40 more nights as a final act of faith. But, as true mother would say, they have an eternity to get to know each other. Juju chang, abc news, south korea. And you can see the full report on nightline prime tomorrow night. When we come back here the epic jam session when new rock royalty was crowned. Its our friday instant index. But i dont want my breathing problems to get in the way my volunteering. Thats why i asked my doctor about breo. Oncedaily breo ellipta helps increase airflow from the lungs for a full 24 hours. And breo helps reduce symptom flareups that last several days and require oral steroids, antibiotics, or hospital stay. Breo is not for asthma. Breo contains a type of medicine that increases risk of death in people with asthma. 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For this toddler . It was a dreaded trip to the car wash. Moments later, the blanket comes off. Turns out, it wasnt so bad after all. We did it car wash all done reporter all done. And so is this weeks instant index. Im paula faris. And next here, boston strong. A mothers comeback journey, a message of strength and hope for everyone. And shes our person of the week tonight. You know how things work. This is the age of knowing what needs to be done. So why let erectile dysfunction get in your way . Talk to your doctor about viagra. 20 million men already have. Ask your doctor if your heart is healthy enough for sex. Do not take viagra if you take nitrates for chest pain; it may cause an unsafe drop in Blood Pressure. Side effects include headache, flushing, upset stomach, and abnormal vision. To avoid long term injury, seek immediate medical help for an erection lasting more than four hours. 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Two full servings of vegetables my feet felt so heavy at the they used to get really tired. Until i started gellin. I got dr. Scholls massaging gel insoles. When theyre in my shoes, my feet and legs feel less tired. Its like walking on a wave. Dr. Scholls massaging gel insoles. Im a believer anybody have occasional constipation, diarrhea, gas, bloating . One Phillips Colon Health probiotic cap each day helps defend against these digestive issues with three types of good bacteria. I should probably take this. Live the regular life. Phillips. And finally tonight, a portrait of strength and spirit. Tuesday marks one year since the terror attack on the boston marathon. And tonight, a mother is making her comeback with a message of hope. Heres david muir. Reporter it was a moment we will never forget. In that hospital room celeste corcoran, a devoted mom and wife, and a double amputee after the boston bombings, about to be paid a visit. Marine gabe martinez, also an amputee, telling celeste at the time, this is not the end. This is a new beginning. And listen closely to what she told him. I cant do anything right now. Right now, yes, but im telling you, and with all my heart, you are going to be more independent than you ever were. That means im so glad to hear. Reporter wiping away her tears as the marine promised bright days ahead. Afterward, offers of help pouring in from all over the country. Then, that video from the family, a mother determined to not let the bombers win. Reaching a milestone on the treadmill. And look at this. The physical therapists at prosthetic and Orthotic Associates in orlando helping her run, each holding straps to keep her upright. A struggle at first, but she finds her way. You can hear loved ones, stunned. Oh, my god. Reporter now climbing to heights unimaginable. One more grip to the top. Unbelievable. Reporter they sent us photos of that first run in that rehab center, with no straps, no help. The first time that i did it myself like i literally kept saying to myself, i cant believe i just did that. I cant believe i just did that. I just did that by myself. Reporter every step celebrated by the husband who helped save her the day of the bombings. Shes the glue that holds our family together, without a doubt. She is my inspiration. Shes a lot tougher than i am. Reporter and she called us that night. She bought a new car, celebrating with a margarita. Knowing in the days ahead, she would have to learn how to drive again. All of this steering her back to where this journey got its unexpected and horrible start. Near the finish line of the marathon, where shell be back with her daughter. Waiting for her sister to round that final bend. My dream is to be at the finish line. I think of us Just Holding Hands and just crossing the finish line. The three of us together. So we chose celeste as our person of the week, with thanks to david muir. Abcs bob woodruff hosts dream on stories of bostons strongest. Torment tomorrow at 4 00 p. M. On abc. We thank you for watching tonight. Were always here on abcnews. Com. Remember, 20 20 later. David muir will be here all weekend. Well see you then, and well see you back here on monday. Good night. Tonight after manl of a tour bus tragedy. Investigators begin to unravel this mystery. Shes really just lucky to be alive. This mans daughter was on board that bus. Well have Live Team Coverage tonight the return to terra firma. A yacht race that nearly ended with the loss of a sailor at sea the Million Dollar discovery in a bay area home now headed back where they belong. Fantastic never looked better the tearful reunion of a teenager and family he survived the crash of a tour bus filled with collegebound High School Students it could be months before we know what happened. We know a fedex driver drifted across the Center Divide and hit the bus head on. The highway did reopen this afternoon. Students were from southern california. The crash occurred near orland just west of chico. This is a College Preview weekend were live now at one hospital where survivors are being treated. Investigators are just beginning what is expected a complex investigation. The process of grieving and recovery is just beginning