When Grover's daughter is kidnapped by an old nemesis, he is forced to help steal $100 million in order to get her back. Meanwhile, Wo Fat escapes prison and heads back to Oahu.

When Grover’s oldest and closest friend tells him he witnessed his wife fall off a cliff to her death, Grover’s gut instinct tells him that this was no accident. Also, Danny and Dr. Shaw get trapped in an elevator with a dead body in need of processing.

On the eve of Kono’s wedding to Adam, Five-0 must stop a fanatical patriot intent on starting a new war on terror by detonating stolen nuclear warheads and framing a terrorist leader.

As Five-0 investigates a double homicide involving marital infidelity, McGarrett and the team recount their disastrous Valentine’s Day experiences.

A case from 15 years ago forces Grover to take his family on the run when a dangerous mob boss tracks him down to seek revenge.

When a man accused of killing his wife threatens to commit suicide, Grover reveals how he too was once on the brink of taking his own life.

Thanksgiving brings Grover’s parents and brother Percy Jr. to Oahu for a visit tainted by sibling rivalry, and Five-0 investigates a thief who is crushed to death by an empty safe.

Five-0 teams up with a DEA agent to search for a killer whose plane crashed in the jungle with $10 million worth of heroin on board. Also, Grover is thrilled when his niece Siobhan comes to try out for the University of Hawaii basketball team.