A woman finds a phone connected to the future, she is tasked by people to do a series of increasingly extreme tasks in an attempt to fix their present, or it may be her latest bout of mental illness.

We don’t know she is mentally ill in the beginning. But she decides to help the future people. They know a lot about her and they sent this phone back so she would find it and help them. Her actions get more extreme. But finally she resolves their issues and their ability to communicate with her is lost. This is when she is confronted by the possibility it was her mental illness.