Five-O investigates the murder of Thomas Hoapili, a local business owner and relative of Kamekona, who was beaten and then shot to death in the trunk of a car. Initially, Kamekona thinks some local thugs are behind the killing, since one had been tailing him for months. However, when Thomas' daughter, Maggie, informs Five-0 that he was actually a Lua master (ancient Hawaiian hand to hand combat), the team starts to put the puzzle pieces together differently. The team eventually discovers that one of Thomas' old Lua students, Walter Palea, was banished from the Lua community years ago by, and it's likely that Palea wanted revenge on him. As Five-0 searches for him, Palea kidnaps Maggie and forces her to fight in a deadly underground Lua/MMA match. Maggie holds her own in the fight thanks to her father's teaching, but she nearly meets her end when Palea joins the fight and unleashes a furious series of hits on her. Luckily, Five-0 locates the fight and subdues Palea before he can do any further harm to Maggie.
Meanwhile, McGarrett has his old friend, Mick Logan, run surveillance on his mother. Doris makes him as a tail almost immediately, but strikes up a conversation with him and winds up liking him. Later, McGarrett is surprised to learn that Mick is going on a date with his mother.