McGarrett and Danny finally track down the missing uranium, which has been built into a bomb located in the middle of the jungle. Now, they must carefully extract the unstable bomb through treacherous terrain before it detonates.moreless
Happy, Sylvester and Cabe need saving from their own fear-based hallucinations when their mission to safeguard a vital seed bank goes out of kilter.
McGarrett and Five-0 once again become entangled in the twisted mind games of serial killer Dr. Madison Gray when she stumbles into HPD covered in blood that matches Alicia Brown's and claims she has amnesia.moreless
Molly's father Mitch returns to the States and Diana questions whether she should renew her relationship with her. Meanwhile, Jenny confines Jobe within a warded circle and questions him for information.
Walter and Sylvester go undercover as competitors at an international-chess competition in order to extricate a U.S. spy from a foreign country before her identity is exposed.
McGarrett and Danny celebrate Valentine's Day with their girlfriends, while the rest of Five-0 investigates the murder of a man taking a class on how to land women.
Ichabod and Jenny take the others to Sleepy Hollow to recover the fourth piece of the Stone, only to discover Malcolm and Jobe waiting for them.
Team Scorpion's latest job to find sunken treasure goes amiss when Walter and Paige's boat explodes, leaving them stranded in the Pacific Ocean surrounded by sharks.
Five-0 investigates a murder involving the illegal practice of shark finning and, during the probe, uncovers the possibility that a former Nazi war criminal may be hiding out in an old leper colony in Hawaii.moreless
Malcolm's old partner pays him a visit, just as Ichabod and Diana confront Malcolm with what they've learned. Meanwhile, Diana worries about whether she's a good mother as she considers how tell Molly that the girl is a Witness.moreless
A spider demon forces Ichabod to face his inner demons in a courtroom with Henry as the prosecutor. Meanwhile, Malcolm sends Jobe to recover a vital map from the Smithsonian while Ichabod's allies to try find a way to bring him back.moreless
The team must rescue a man teetering on the edge of a massive sinkhole that threatens to destroy Los Angeles' water supply.
Five-0 must negotiate between the law and local customs when a man wanted for murder escapes capture and seeks asylum in sovereign land belonging to the Nation of Hawaii.
The Horseman returns... and travels to DC to take a new head: the President. Ichabod and Diana go to Malcolm for help, unaware of his true intentions. Meanwhile, Jake and Alex find evidence confirming Ichabod's original age and confront him with the truth.moreless
The team is tricked into producing counterfeit money for a foreign entity that's seeking to run the U.S. economy, leading Paige to turn to her mother's grifting skills to bail them out.
A murder is the result of witchcraft, and Diana calls Ichabod in to help the investigation. Meanwhile, Ichabod and Jenny uncover the identity of the new Witness.
Ichabod ends up in DC trying to find the next Witness. Meanwhile, a demon possessing the body of John Wilkes Booth is freed, and the vengeful partner of its first victim is on its trail.moreless
The team must freeze Cabe's body in order to save his life after he's seriously wounded by exploding shrapnel while on a mission in the desert.
The team's electronics-free getaway in the mountains on Christmas Eve takes a dangerous turn when they encounter a group of gunrunners who kidnap Ralph. Meanwhile, Tim makes an important decision about his role with Team Scorpion.moreless
Walter's forced to swim through the deadly La Brea Tar Pits in order to save a woman who's trapped in the tar before she runs out of oxygen. Elsewhere, Veronica helps Ralph with his troop's cookie sale, unbeknownst to Paige.moreless
Paige's estranged mother enlists the team's help when she accidentally uncovers a forgotten nuclear reactor that's on the verge of exploding.
The team travel to Ireland to attend Megan's memorial, but Walter discovers a natural disaster in a nearby lake created a poisonous cloud that's threatening the entire village. Meanwhile, Cabe and Toby try to alleviate tension between Tim and Walter.moreless
Danny chaperones Grace's winter formal but terrorists seize the venue and hold everyone hostage in order to kidnap a diplomat's son. Also, Danny and Grover are shocked to learn that Will is Grace's secret boyfriend.moreless
The team must stop someone who tries to intervene in the U.S. presidential election on Election Day.
The team must stop thieves who robbed a rare-gem exhibit at a museum in order to extract materials needed to enrich a nuclear bomb.
The team searches for a boy from Ralph's class who encountered a deadly criminal after going missing from a field trip. Meanwhile, Toby gets closer to uncovering the identity of Happy's husband.
McGarrett and Alicia are kidnapped by the serial killer who has been terrorizing the island after they discover his identity.
Walter's accidentally launched into space, where he hallucinates about Paige as his oxygen runs low. Meanwhile, the team rush to return him to Earth before he suffocates.
FBI profiler Alicia Brown is forced to join McGarrett in the hunt for the chess-piece killer when she finds a body in her bed. Meanwhile, Kono reconnects with a former surfing competitor who is now a disabled and homeless war veteran.moreless