Five-0 needs the help of an imprisoned bomber to find a copycat on the loose, but is he somehow related to the crime? Meanwhile, Kono and Adam discover that they're being watched after Adam recovers from the shooting.
Five-0 investigates when a wealthy recluse is found dead in a remote field with nearly one million dollars in counterfeit bills. Also, Adam is kidnapped by the Yakuza and forced to torture one of Gabriel's men. Jerry Rice guest stars.
Five-0 interrogates members of a stunt biker gang to locate a killer who escaped by jumping his motorcycle from one rooftop to another. Meanwhile, the riders prepare to race in a Tough Mudder competition.
Five-0 is in search of a serial killer who may be a modern-day Dr. Frankenstein, while also dealing with a hostage situation after a blood bank robbery. Meanwhile, Danny is frustrated after Grace goes to a Halloween party behind his back.
While snorkeling off a deserted island McGarrett and his new girlfriend stumble onto the hideout of a wanted gangster while Chin, Kono and Grover must track down a gambler who is forcing a high school quarterback to throw a playoff game.
Five-0 works with a conman to find a killer after his partner is murdered. A San Francisco police inspector helps Chin Ho investigate the murder of Chinese arms dealers. Adam receives some unsettling news after meeting with the Yakuza boss.
After a college professor is murdered, Danny goes undercover as his replacement and Eric poses a college student. McGarrett gives advice to a young man after his dad returns from jail and wants to get back in his life.
The brother of a local boxer is killed the night before his championship bout, and Five-0 connects it to Gabriel Waincroft, who has an even bigger target in mind. Meanwhile, Adam takes a plea and prepares to serve his sentence.
Five-0 uncovers a Japanese World War II spy mystery after a young boy is shot in a long-forgotten bunker. Meanwhile, Aunt Deb returns to Hawaii to visit the McGarretts so she can help finish her recently-deceased husband's "bucket list."