In flashback, we learn that Montana and the Night Stalker met during one of her classes. 

He butchered a man who made fun of her and they had sex while the body bled out around them. 

Montana opened up about her brother being murdered and how it was all Brooke's fault. 

That's why the Night Stalker went after her. 

Montana found Brooke strung up in a trap and alerted her boyfriend to her whereabouts. 

When the Night Stalker showed up, he was forced to fight with Mr. Jingles. 

Brooke escaped while that was playing out. 

In the end, Mr. Jingles killed the Night Stalker. 

Brooke found her way back to the others. Mr. Jingles then arrived at Margaret's cabin to learn that she was the one who carried out all of the murders and that she pinned it on him. 

She said that his return put a spanner in the works, and that she would need to kill again. 

She tried to kill him but he escaped. She then killed Trevor. 

Donna woke up after a fight with Montana and found the Night Stalker coming back from the dead. He then went after her. 

Xavier was forced to kill Bertie after she saved his life.