Carrie notes it's time for Doug's 10 year anniversary at work and since his extended benefits have not yet kicked in, she wants to call his work and find out why.
This leads to Doug confessing that he really didn't start work at IPS when Carrie thinks that he did.
Doug shows how immature he was (is?) in that he lied to Carrie about having a job just so that Carrie would sleep with him. She doesn't quite trust him so she follows him to work and Doug just sort of pops into IPS and pretends to work there. Eventually Carrie shows up at work and Doug tries to show off and damages things. The boss fires Doug, only to learn that Doug was never an employee. Doug has a solution - hire him and he'll do a good job. So Doug gets his job finally and his own truck.
This episode is very funny but the writers missed the boat by not concluding with Carrie's reaction to the tale. Instead they close with a useless scene about Spence getting spoiled about a "Melrose Place" plotline.