Kathleen and Larry work in the same company. It is about a rather big company which employs many people. And because this company needs a lot of people, it is hard to find so many good workers, so the employees in the company change very often. On the other hand, the company where Kathleen and Larry work is every day visited by many clients which means that it is very hard to control who enters and who exits from the company's building.
This is very important in the actual situation. Namely, Kathleen and Larry have noticed that someone is stealing their personal belongings. They can't guess who might be the thief because of the previously mentioned situation. It might be someone from their colleagues, but also it might be someone from their clients.
Kathleen and Larry decide to take the situation into their own hands and find out who is responsible for those robberies. It will be hard, because they are meeting so many people every day, but they are sure that, somehow, the thieves will reveal themselves.