As Morgan drives from Mile Marker 54 to The Flip-Flop Truck Stop in Martha's stolen police car, he gets a radio call from June that something is wrong and his friends are all getting deathly sick. Desperate to stop Morgan from reaching his friends and saving them, Martha purposefully causes the car to crash in this location and stabs a piece of metal into Morgan's leg in order to hobble him.
When Morgan regains consciousness, Martha reveals that she has purposefully allowed herself to be bitten on her gunshot wound in order to prevent Morgan from being able to save her and attempts to push Morgan over the edge so that he can become the dangerous man that he was before and be "strong" again. Morgan gets repeated radio calls from his friends who eventually realize that they have been poisoned and Martha reveals that she had put anti-freeze into the truck stop's water bottles and there's nothing that Morgan can do to save them. Morgan finally snaps and nearly strangles Martha to death, but regains control of himself rather than give in. In order to keep Martha from harming anybody else when she inevitably turns, Morgan handcuffs her to the police car and takes off to save his friends.
After saving the others, Morgan returns to the location with the others only to find that Martha has died, reanimated and ripped off her own left arm in order to escape. Morgan spots the zombified Martha walking down the road a short distance away and puts her down with his staff. Morgan then buries Martha on the rocky hillside where she died and announces to the others his plan to continue Clayton's mission of helping people rather than going to Alexandria as he had earlier intended to do.