Jamie's conduct is questioned when a suspect he was pursuing is fatally injured. Baez goes under cover to investigate a drug dealer, who is the fiance of Danny's ex-girlfriend.
Five-0 must protect the sole witness in a high-profile murder case, a task that grows even taller when it turns out that multiple assassins are targeting her.
The team's investigation into the murder of a wealthy restaurant owner causes McGarrett to take part in a charity MMA fight to the finish. Meanwhile, NCIS Agent Kensi Blye lends her expertise to McGarrett and Lt. Commander White when they ask her to examine a video of McGarrett's father.
The team enlists an old friend when a crime boss is murdered, triggering revenge killings across the island; MacGarrett and Danny work out details concerning their new restaurant venture.
Jack learns to appreciate the spirit of Leap Day, while Tracy attempts to spend a $50,000 gift card 24 hours before it expires.