When Arkham Asylum was in dire need of a new Head of Security, Bruce Wayne felt Lyle Bolton, a security expert at Wayne Enterprises, was the perfect man for the job. What Bruce and the doctors at Arkham did not know was that Bolton pushed the boundaries of the law and used unnecessary means to keep his prisoners in line. Bolton proved so malicious that the Scarecrow, the "Master of Fear" himself, escaped Arkham just to get away from him.
Bruce Wayne became suspicious about how Bolton was keeping the Arkham inmates in check so well, and about the complete terror Bolton had instilled in Scarecrow, so he set up a hearing with Mayor Hamilton Hill, Commissioner Gordon, and Dr. Bartholomew, chief of medicine at Arkham. After questioning the uneasy inmates of Arkham, including The Ventriloquist, Harley Quinn and Scarecrow, Bruce Wayne discovered that Bolton had been torturing, threatening, and assaulting the inmates, including holding Scarface (who in this episode resembles Bolton) over a can filled with termites. Following a blowup at the hearing, where he assaulted several Arkham orderlies and attempted to attack his accusers, Bolton was relieved of his post at Arkham.
After his release, Bolton called the city "an open wound" and became convinced that the press was supporting crime by glorifying criminals on television, assisted by a legal system seemingly set up and enforced by both the politicians and police to serve as a revolving door for criminals instead of bringing final justice to them. Bolton then created a costume and tools, started calling himself Lock-Up and began to arrest the people he deemed to be at the root of Gotham's problems. He imprisoned Mayor Hill, James Gordon, reporter Summer Gleeson, and Dr. Bartholomew, and held them hostage aboard USS Halsey F-84, a decommissioned battleship. The hostages were freed by Robin while Batman defeated Lock-Up. Lock-Up was placed in a cell in Arkham, where he was mocked by the same inmates he once tormented. Bolton wasn't too bothered by this though, because now he could keep an even closer eye on "his" prisoners stating that "they'll never slip past me again".
- Lock-Up also made the leap to The DCU in the New 52, surprisingly before Harley.