Queen of the Assassins by Stacey Brutger

THOUGH THE ACADEMY IS AT PEACE, THE OUTSIDE WORLD IS STILL IN TURMOIL, LEAVING THE ASSASSINS TO FIGHT THEIR DEADLIEST FOE YET—THEMSELVES.

A cold case. A coven gone dark. Morgan and her men decide to take some time away from the Academy to cement their bonds and investigate the mysterious disappearance. Unfortunately, what should’ve been a routine mission quickly goes sideways when they’re attacked, turning their intimate vacation into a nightmare.

The weakening wards around the coven are the only thing keeping the evil from spilling into the human world…and holding the Assassins captive. Escaping would mean leaving one of her own behind to battle the ancient evil alone. Not happening.

Which means they need to discover a way to send the beasts that escaped from hell back to where they belong…before Morgan and her men become monsters themselves.