When a Detroit hit man is taken out by one of his colleagues on the streets of Oahu, Five-0 is shocked to learn the killer's surprising motives. Meanwhile, Chin puts his career on the line to help Danny get the money he needs to save his bother's life.

It's Halloween and Five-0 must track down a serial killer who is copying murders depicted in a cult slasher film. Meanwhile, McGarrett must help Jerry after he is kidnapped by the counterfeiters he has been tracking.