The Hollow Earth (2018)

Miles has moved to a new city, gone "underground" with his filmmaking, and cut most of ties with the life he used to lead, and the people he used to know. So it is an unsettling surprise when Karen, the mother of a troubled, fiercely-talented ex-lover of his, shows up unannounced at his studio door. Ruth is missing, and Karen has a cryptic last letter her daughter sent before disappearing; It says she hooked up with a man she refers to as her "soul guide" in a place she calls the Hollow Earth. And Yes, Miles does know where she means...sort of. Miles and Karen cared little for each other in the past, but they are the two people in the world who know Ruth best. Miles makes a fragile bargain with Karen - to look for Ruth, to make sure she's okay, and to let Karen know. Neither is really prepared for what happens next.