The Green Hornet discovers a photo electric cell at the site of a subway construction site phony explosion and believes the foreman for the company is responsible for the destruction, but he must prove it.; The murder of a Sentinel reporter leads the Hornet to track down the murderer by pretending that Martin is still alive and still writing for the paper.; The Hornet investigates a vicious racket of using residents of a home for the aged as slave laborers that profits the big boss named Riko.; A crooked politician puts the blame for the murder of a shyster lawyer upon the woman he is representing.; A series of taxi cab explosions leads to the Hornet's investigating and discovering that fuse-type bombs are being planted in the cab's radios and exploding during operation.