An escaped convict who wants Five-0 to prove his innocence abducts Danny and McGarrett; Grace punches a person at school.

When Five-0’s sketchy confidential informant is accused of murder, McGarrett asks his old friend Odell Martin to defend him.

At Halloween, Five-0 must investigate a string of murders that mirror stories from well-known Hawaiian folklore. Also, Grover is called to visit a man hours away from execution who may hold the key to a case that has plagued Grover for years.