McGarrett’s first date with Lynn on a deserted island turns deadly when a mob boss hiding there hunts them down in order to keep his location a secret. Also, Chin, Kono and Grover must race against the game clock to locate the father of a high school football star who will be murdered by a local gambler if his son doesn’t throw the big game.

As Five-0 investigates a double homicide involving marital infidelity, McGarrett and the team recount their disastrous Valentine’s Day experiences.

Five-0 must free McGarrett's mother, Doris, when Catherine informs them that she was captured and is about to be executed after attempting to free Wo Fat's imprisoned father. Also, Chin loses his appeal to have Sara's adoption delayed, and she must move to Mexico.

While McGarrett and Danno celebrate Valentine's Day with their girlfriends, the rest of Five-0 investigates the murder of a man taking a class on how to land women.