The latest on a puzzling disappearance - a young groom who vanished during a honeymoon cruise through the Mediterranean. One minute he was partying with some new friends, the next, he was gone. There were reports of loud noises in the couple's cabin. And - perhaps most frightening of all - blood found just below the groom's balcony. Four years have gone by, but his bride and his family still have no idea what happened. NBC's Dennis Murphy reports on a mystifying "Disappearance Before Dawn."

Also: The latest on one of the most dramatic of the investment scam stories that have rocked the country lately. Back in January, Marcus Schrenker, a high-flying financial adviser accused of wrongdoing - and a pilot - radioed air traffic controllers that his small plane was going down. At that moment, investigators say, he strapped on a parachute and put in motion a daring plan to fake his own death and hide his double life. NBC's Keith Morrison has a new interview with his wife in "Flying High at Cocktail Cove".

See it all on a two-hour Dateline Friday, starting at 9 p.m. ET, 8 p.m. CT.