Andrew Lawrence

When a young couple decides to go skinny-dipping in a hot spring, their spontaneity is ruined when they find the remains of a skeleton in the mud. Brennan and Booth soon discover the skeleton is that of Tripp Goddard, a professional motorcycle racer who just won the Super Grand Prix. The team immediately suspects Danny Fitz, the runner-up in the race and Tripp's main rival, to be the murderer. But just when Brennan and Booth think they have it solved, a fiery motorcycle crash claims another victim, and the circumstances seem far from accidental. Meanwhile, Dr. Lance Sweets forces Brennan and Booth to join him on a double-date in an effort to encourage them to interact in a social setting, away from any of their cases.

Castle and Beckett investigate the death of a champion swimmer; authors Michael Connelly and Dennis Lehane give Castle advice.

Sergeant Gabriel shoots a murder suspect he is certain is armed and firing at him, but his account does not match up with the evidence. Captain Sharon Raydor (recurring guest star Mary McDonnell - "Battlestar Galactica," "ER," "Independence Day," "Passion Fish"), the head of the Force Investigation Division, is responsible for investigating the shooting. However, Raydor's investigation is interfering with Brenda's investigation into the murder, which may have been ethnically motivated.

When the bodies of two serial killers are found on Five-0 property with chess pieces in their mouths, McGarrett and the team hunt for a vigilante as fear grows that tourists aren't safe in Hawaii. Rosalind Chao guest stars as Governor Keiko Mahoe.

While Five-0 investigates a scuba diver's death from a gun recently used in another murder, McGarrett prepares to propose to Catherine. Andrew Lawrence and Michelle Borth return.