"Two's a Crowd" is the 13th and final episode of the first season of Superman: The Animated Series, and the 13th of the overall series. It depicts the return of Parasite, who has now absorbed the mind of the scientist Earl Garver. Superman now has to deal with a man of high intelligence in the body of a being that can steal his powers. To make matters worse, a bomb is set to go off in Metropolis and can take out three miles of the city.
Things look bad as the SCU surrounds a house. Maggie Sawyer calls up the inhabitant of the house and she and Professor Hamilton try to coax him out of the building. He refuses, forcing the SCU to attempt a raid. However, the house is barricaded with steel walls and automated weapon systems. All attempts to enter into the house are met with failure. Superman shows up and asks about the situation. The man in the house is Earl Garver, a former employee of S.T.A.R. Labs who has stolen a radioactive isotope from S.T.A.R. and made a bomb that can destroy three miles of the city. The lead-encased bomb is set to go off unless Garver gets paid fifty million dollars in ransom. Superman makes his own assault on the house.
Inside the house, Superman finds that there are more defenses, such as electrified walls and a powerful gun. However, he manages to overcome even these defenses and confronts Garver. Cornered, Garver activates a hydraulic press and attempts to crush Superman, but finds his enemy is far too strong. Superman pushes back the press and crushes it, but a large cable knocks Garver out, giving him a concussion that will render him unconscious until well after the bomb will go off. There is far too little time to find the bomb, and without knowing its location, even Superman cannot stop it. Realizing they do not have much of a choice, Hamilton makes a rather bold suggestion.
Superman, Hamilton, and Sawyer head off to visit the Parasite, hoping to use his ability to absorb people's thoughts to get the location of the bomb from Garver. He seems uninterested, but then makes a deal with them: he will do it in exchange for having cable TV, premium channels included. Parasite goes to Garver and touches him. Unfortunately, something goes wrong and Garver takes over Parasite's body. Garver insists that he still get paid for the bomb to be stopped. Superman points out that Garver may go with the bomb if it goes off, and, seeing there is no other way out of it and at the urging of Parasite, he reluctantly tells where to find it.
Superman and Sawyer go towards Metropolis Harbor and search an abandoned ship. Superman is unable to see through the debris, so they have to go inside to search. Eventually, Sawyer realizes the bomb isn't there. Superman claims that Garver is just buying time and heads back to the hospital.
Back at the hospital, Superman's suspicions turn out to be true. Garver attempts to escape from his restraints and finally convinces Rudy he can find a way to make the Parasite's drain permanent in exchange for his help, reasoning this could be his last chance for freedom and power. Rudy joins his will and strength with Garver's and the two manage to destroy the hand restraint. Garver then calls in the guard and steals his strength as well. With his increased might, he manages to escape his bonds and takes the life force of many members of the hospital staff. With only twenty minutes left before the bomb goes off, Garver calls up and demands his money, but this time Superman must bring it himself. Superman brings in the money to an abandoned rail tunnel, following a set of audio instructions, and discovers a pit so deep even he can't see the bottom. Near the pit, he finds the bomb and deactivates it. However, it turns out to be a trap, as the Parasite grabs him. Garver reveals he wants not only the money but Superman's powers as well. The two struggle and seem to be evenly matched. Knowing he will soon lose his power, Garver reactivates the bomb, changes the deactivation code, and demands that Superman gives him his powers, unconcerned about whether or not it goes off—his body is lying miles away in an ambulance, and won't be harmed. Superman calls to Rudy and turns him against Garver, but in the end, Garver's will proves stronger. Time runs out and Superman throws the bomb down the pit. Garver attacks but both he and Superman fall into the pit with the bomb. The bomb goes off and defeats the Parasite, but Superman manages to escape unharmed.
Outside of the tunnel, Garver wakes up in an ambulance and finds Superman flying him over Metropolis. Garver is taken to prison and finds his old "partner" the Parasite laughing and enjoying himself as he watches his new big screen TV with cable.