This low budget film with the usual cast of characters has Chester Morris, as Boston Blackie coming to the aid of an ex-con buddy who he got to know while serving in the State Penn. His buddy is being released and has some diamonds hidden my his previous business investments and is afraid his old gang will want the diamonds and kill him. Ann Savage, "Detore" is the ex-con's daughter and she wants to look after him and seeks Boston Blackie's help. Richard Lane, Inspector Farraday is still out to handcuff and arrest Blackie for breaking into a locker containing the diamonds. There is train rides and plenty of car chases and Boston Blackie even impersonates an African American in order to disguise himself from Cy Kendall the top gangster. If you like these sequels, you will love this film which runs very smoothly and is enjoyable.