for a very selfish reason i don t want the loch ness mystery or interest in loch ness itself to diminish it ll be hard for nessy to hide from this high tech hunt, launching drones overhead, scouring the surface, while also listening below. we are dropping an under water microphone 60 feet down below the depth. we ll be doing some audio testing to find out what noises exist down there. reporter: they are using sonar to map the lake, which has a depth of nearly 800 feet the maximum depth here, this is the deepest part but it is a huge area. reporter: somewhere in all of this dark water there is a monster lurking but it is up to us to find it or find her. ken gerhart traveled from the u.s. to hunt. he researchers animals on the fringes of known reality.