While Five-0 races to stop a mad bomber before he kills again, Danny gets an unexpected visit from his little brother, Matt, a fun-loving, Wall Street broker. The family reunion is cut short, however, when Danny discovers the real reason that Matt is in Hawaii.

When the Five-0 discover a John Doe in the trunk of a stolen car, they not only have to find a killer, but also need to figure out who the physically-altered victim was. Meanwhile, a homeless Danno is sleeping on McGarrett’s couch.

While the team investigates the murder of a young computer hacker, McGarrett tries to stage a long-needed reunion between his mother and his sister.

The team is directed to investigate when a prostitute is murdered in a Congressman's home, who is nowhere to be found. Danny has his own drama as the custody hearing regarding Grace goes to court.