Parallel is based on Lei Zheng's Parallel Forest. The movie follows Vanessa as she grieves her child and struggles to cope with the loss while her husband, Alex, tries to help her move forward. While in the woods, Vanessa has a shocking experience when she runs into an alternate version of herself from a parallel universe. This revelation sets Vanessa on a reality-bending, mind-altering path that has the potential to help her escape her grief or trap her in it forever.