When a famous radio DJ is killed by an explosion in his yacht studio, Five-0 joins the case to hunt for the person who planted the bomb. Evidence initially leads McGarrett and Danny to Tony Archer, an ex-NYPD bomb technician living on a dilapidated houseboat. Tony turns out to be the godfather to Melissa Bates, the dead DJ's daughter, and he wants to find out who murdered his friend. He teams up with Five-0 to track the murderer down. Eventually, the team discovers that Melissa's husband, Todd Hegman, was part of a wanted con artist team that planned to steal money from the family trust. Todd fell in love with Melissa and didn't want to go through with the plan, so his partner, Karen Rafferty, killed Melissa's father in hopes that Todd would pay her off with the inheritance money. Also, Danny starts to fret over the level of attention Grace is getting from one of the boys in her class.