Who's Guilty? plot
"Who is the invisible killer? What is the unseen death? Where is the assassin's lair?"
Walter Calvert has his brother Henry come to his creepy old house and claim some of the family's wealth. Walter threatens to kill Henry if he doesn't get it. A few days later, Henry's car drives over a rock wall and he is presumed dead. Detective Bob Stewart, whom Henry has asked to investigate should he be killed, begins his investigation. Bob's friend and journalist Duke Ellis helps him with that. Bob meets the family at their home and questions Henry's sister, his half-brother, his cousin, this cousin's bride, and Ruth Allen, whose father was Henry's co-worker.