Cathy Simms was Pam Halpert's temporary replacement while she was on maternity leave in season 8. During her employment, she developed a friendship with Jim Halpert and devoloped an interest in him. Despite his marital status, she planned to seduce him.
Little is known of Cathy's life before her time at Dunder Mifflin, although in a deleted scene she mentions a rich man who had offered to marry her.
Season 8 Edit
In "After Hours" Cathy joins Stanley, Dwight, Jim, Erin and Ryan on a business trip to Florida. Before boarding the bus, Cathy is talking on the phone with an unknown person implying that she believes she and Jim will hook up in Florida. She also mentions her belief that Jim and Pam's relationship has fallen apart.
Upon arriving in Florida, Cathy sticks close to Jim, flirting with him (though Jim does not seem to notice, and doesn't reciprocate) and trying to establish a closer relationship with him. One night, after Jim leaves the group's gathering at the hotel bar early, Cathy looks visibly upset and also leaves. Later, Cathy, dressed in a revealing outfit, shows up at Jim's door where he has been relaxing and watching basketball on TV in his room. She claims that there's a problem with the heating in her room and asks if she can hang with Jim while she waits for it to be fixed. Jim hesitantly agrees, aware of the potentially inappropriate nature of Cathy's visit. He desperately tries to make it so he's not alone with Cathy, even calling Dwight under the pretence that there's bed bugs in his room. Dwight clears the room of the imaginary bed bugs, though his appearance leads to Cathy claiming that she's grossed out and that she needs a shower, which she proceeds to take in Jim's hotel room. When Jim finds her in only a bath robe on his bed, he immediately expresses his discomfort and reminds Cathy that he's happily married to Pam. Cathy, still on her quest to seduce him, feigns shock and disbelief, and assures Jim that her visit is purely innocent. Jim apologizes, though he realizes Cathy is not being entirely honest when she cuddles up next to him in bed. He becomes upset when he comes back from the bathroom to find Cathy under the covers in her lingerie, and tells her that she needs to leave. When Cathy tries to reassure him that she's innocent, Jim calls upon Dwight (once again citing bed bugs), who enters the room with an unknown "chemical compound" and begins spraying it everywhere. This finally forces Cathy out, especially when Jim tricks Dwight into spraying the chemicals onto Cathy, claiming that he sees bed bugs near her. Cathy leaves screaming and Jim ultimately ends up rooming with Dwight.
In a deleted scene Jim calls Pam while Cathy is in the shower. He describes what happened and her obvious intentions, Pam teases Jim about his new "girlfriend", and he ends their phone call by expressing his displeasure with Cathy's unwelcome presence.
Cathy is seen again, during the grand opening of the Sabre store in Florida. She attempts to capture Jim's attention, but he blatantly ignores her. Her last appearance is at the meeting where Robert California fires Todd Packer for the Sabre Store. It is unknown what happened to Cathy, but she is no longer seen at Dunder Mifflin or elsewhere. It can be inferred that Cathy either chose to stay in Florida or was fired alongside Todd Packer.
Cathy is of average height, with medium-length brown hair, brown eyes, and tan skin. Most of the Dunder Mifflin employees have stated that they find her attractive, due to Pam's prodding after she believes Jim has feelings for Cathy in "Pam's Replacement".