Eden Cole - On A Blood Moon MM

Jace leaves his boyfriend home and attends a Halloween party, which turns interesting and then deadly. First he meets two big and sexy men dressed like vampires, and then real vampires attack. When one of the undead drains Jace of his life source, he learns the fake vamps are really werewolves, and they were at the party for him. With no other choice, Gair and Stion do what's necessary to save Jace. Now he is one of the monsters he never knew existed, and the two shifters must stick by him until he learns to control his undying hunger.