Thomas and Samuel race to find a way to expel the demon that controls M and fail. It escapes, disappearing in broad daylight. With Thomas unable to track it down, magically or with science, he's forced to do the one thing he hoped to not do. Thomas has to rely on the advice of a all-powerful being that he wants nothing to do with and use it's 1400 year old demon slayer to hunt down the demon in M.
Will Thomas be able to purge the demon inside M? Even if he can, Thomas has to tell him why he was possessed in the first place. Will M be able to accept Thomas's twisted, tainted and sad past, or will their 100 year old friendship be destroyed, leaving Thomas to deal with yesterdays problems alone.