May's real-world body is taken to the hospital, where Calvin and Bea rush over to meet her. She's in a coma. But… not really: she’s in the mirror world watching this whole absurd thing unfold. The grief is real though!
So are these things. May is being attacked by a small army of dark souls — once-human figures now much decayed — that have fallen upon her behind the mirror. She can’t catch a break, in either world. Luckily, a woman inside the mirror world named Sarah saves her from the ambush, and gets her to safety, STAT.
The family set up a mirror specially for May to be able to communicate with them. Bea uses an ancient bowl without a bottom as a communication device. It works! And just in time too: May’s doctor, Dr. Kim, wanted to pull the plug and harvest her organs (per her organ donor request). Close one.
Sarah is getting hungrier and hungrier, and she actually inhales — through her palm — some of the dark souls that threaten them in the mirror world. OK, so Sarah isn’t who she said she is: she’s an infernal feasting on the people that get trapped in the mirror, but she wants to get out into the real world now. May can help her do that. So Sarah attempts to wear May's body like a suit.
Calvin crosses over into the mirror world to save May and vanquish the lost souls that are threatening her life. He does this by shining lights in their faces and setting them on fire. It's flawless logic. They escape the house May is being held captive in, and attempt to make it back to the hospital where May can cross back over.
Sarah ultimately blows up in the mirror world, and to prevent their worlds from combining, Tilly has to push that genie back in the bottle. Figuratively speaking. Or maybe, given the circumstances, not so figuratively speaking?