On Halloween, Jerry and his friends search his childhood camp for evidence to a murder he witnessed as a boy, while McGarrett investigates a little girl who drew pictures depicting the scene of a recent murder before it was discovered.

McGarrett investigates a cold case from the 1940s, one that his grandfather and the famous Honolulu detective Chang Apana worked on, and he tries to deduce how the case could have been solved. Also, McGarrett and Danny get ready for the opening of their restaurant.