Breen was a New York City police officer. He replaced James McIlveen as Tessa Mancuso's partner. During a drug store robbery, he arrested Ace, who was at the scene of the crime, while his partner went after the Seventh Doctor. After they had captured the robbers, he took Ace into custody, but when he found that she had been released into the custody of the Butler Institute, he made Stephanie and Mulwray let her go and took her to Mancuso at R&D, where she was reunited with the Doctor. (PROSE: Cat's Cradle: Warhead)