The quality of violence in the Montreal underworld is a revelation. Dark alleys, over severs ever yawning for bodies of the slain, are traversed and analyzed by Mr. Michael Brent, the brilliant Montreal attorney who is defending a man accused of two murders. The case is dead-open-and-shut in the minds of the police, who are certain of conviction but Brent, the attorney, suddenly comes to the conclusion that the prisoner had nothing whatever to do with the infamous crimes. Brent's investigations lead him directly to the scene of a third murder after which his assorted and violent experiences are capped with this one which is here repeated for a reason soon to be explained! Walking along in the dreariest section of Montreal's slums, Brent is accosted by a little man whom he has seen before but can't recall. The man acts suspiciously, seeking to strike up a conversation and clearly indicates that he knows the trend of the lawyer's investigations at the house "Number Ninety".