Executive Harold Clark infiltrated Vault 51 in Appalachia by taking on the identity of a scheduled resident that failed to show up. His objective was finding out what was going on in Vault-Tec's vaults, and to report back to the company board with the information. Clark, Clark, Clark & Associates had fallen on hard times, with Harold blaming it on his brothers' incompetence, but hoped to make the company more competitive with the new information. The company also had some sort of science division with a lab. Harold eventually realized that, after the Great War, everyone on the board was dead and began to panic, theorizing that Vault-Tec had led him to Vault 51 as a trap, given the instability inside.