>> reporter: it is the dark mystery at the heart of donald trump's presidency. >> why is he so chummy with vladimir putin. >> he's creating a hero out of vladimir putin. what the hell is going on? >> reporter: speaker of the house nancy pelosi summed it up this way. all roads lead to putin. >> reporter: donald trump wins the presidency -- >> in november 2016 trump's victory was a political earthquake in the u.s. but in moscow it sparked joyous celebration. >> we are the champions of the world. >> reporter: he was meeting outgoing president obama. >> settle down. >> reporter: and obama gave his successor a piece of advice. do not hire michael flynn. trump did it any way. the new national security adviser lasted just 24 days. flynn had lied about russia.