Monk undergoes hypnotic therapy as treatment for his OCD. After a session, he adopts a more childlike personality. Meanwhile a soon-to-be divorced woman disappears and a murder occurs.

Sheldon is overexuberant that Leonard finally has a girlfriend matching his high standards.

Lake returns to the SVU and works with Tutuola when Tutuola needs to handle some unresolved issues with Darius.

While Mac dines at his local breakfast spot, a gunman opens fire, leaving a waitress critically injured and a man dead, and Mac having to choose whether to chase after the suspect or save the life of the young woman. Meanwhile, before the chaos, Mac was approached by a shy patron who awkwardly engaged him in conversation. After feeling that he saved her life during the shoot out, she asks him to join her for a drink and Mac must decide if he is ready to start dating after his wife's tragic death.

Two scientists confer about each of their metal objects that were found in Africa and they theorise that the objects are pieces of a puzzle which could be undeniable proof that human, plant and animal life did not originate on this planet. When one of the scientists is killed and the objects are stolen, the agents investigate and Mulder begins to experience severe neurological pain caused by the objects.