A neurosurgeon is assassinated just before performing a surgery. The investigation uncovers the truth behind the disappearance of four reform school boys over 40 years ago. Meanwhile, McGarrett's beloved Mercury Marquis is stolen by an unlikely culprit.

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.

While Danny chaperones Grace’s winter formal, terrorists seize the venue and hold everyone hostage in order to kidnap a diplomat’s son

A renowned urban vigilante is killed after making another citizen’s arrest, and Five-0 delves into the world of super heroes and comic books to find the killer. Also, Adam finally gets closer to finding out who killed his sister.