From NetFlix:

Dr. Sam Frank is haunted by his first love, an unforgettable romance that ended in loss and terror. Years later, he’s become an expert in the psychology of repression but remains a loner. Then, a beautiful stranger on a train changes everything.

At the end of this quiet, slow, sad love story, do not expect everything to have made sense. Just appreciate the parallel between Sam’s boyhood first love and his encounter as an adult with Helena Bonham Carter. Expect a semi-happy ending of acceptance with a bit of magic realism thrown in.