Killer Croc is having a nightmare wherein he sees himself being tortured by the orderlies at Arkham Asylum. Lashing out, he attacks one of his new friends in his underground shelter. An elderly woman named Aunt Marcy consoles Croc and convinces him to release the frightened homeless man. Croc calms down and sets to improving the living conditions for his new acquaintances. Aunt Marcy's son asks Croc about his missing dog Spot. Croc tells him that he will look for the animal for him.
Batman investigates a break-in at Taylor's Exclusive Shopping outlet. He finds a hidden stairwell behind a snack machines. He radios Robin at the Batcave and tells him that Killer Croc may be responsible for the robbery, Robin warns him to stay out of tunnels. The city implements a new system, and tunnels will be flooded at midnight.
Batman takes Ace and together they exploring the labyrinthine tunnels. Ace runs into a sewer pipe and finds a lost dog Spot. He saves him from hungry rats. Batman catches up with Ace and soon discovers a weakened section of wall. He breaks it down and finds that it leads to the fallout shelter where Killer Croc's friends reside. Croc catches Batman's scent and attacks him. They fights and Batman barely manages to evade Croc's crushing blows. Suddenly, he hears the sound of rushing water. Batman warning him that the tunnels are going to be flooded. Croc presses up against the weakened wall, Batman get Aunt Marcy and the others higher. Croc is washed away.
