Donnie tries to help a war hero suffering from a neurological disorder, but what starts out as a good deed ends up having major implications. Meanwhile, Pierce gets an unexpected surprise when a fling from his past shows up.

With the help of his hallucination, Hall of Famer Mordecai "Three Finger" Brown, Pierce fights for an autistic teen under interrogation for murder. Meanwhile, Dean Haley turns on the charm in order to convince a neuroscience prodigy to attend CLMU.