Buffalo Jump - Howard Shrier

Toronto investigator Jonah Geller is at a low point in his life. A careless mistake on his last case left him with a bullet in his arm, a busted relationship and a spot in his boss's doghouse. Then he comes home to find notorious contract killer Dante Ryan in his apartment - not to kill him for butting into mob business, as Jonah fears, but to plead for Jonah's help.

Ryan has been ordered to wipe out an entire Toronto family, including a five-year-old boy. With a son of his own that age, Ryan can't bring himself to do it. He challenges Jonah to find out who ordered the hit. With help from his friend Jenn, Jonah investigates the boy's father - a pharmacist who seems to lead a good life - and soon finds himself ducking bullets and dodging blades from all directions. When the case takes Jonah and Ryan over the river to Buffalo, where good clean Canadian pills are worth their weight in gold, their unseen enemies move in for the kill.