According to Jim

It's Halloween and Cheryl is trying to host "the" party so she can own Halloween in the neighborhood. Dana brings in her newest date, Hank, who carries an awful lot of similarities to Jim. While refusing to admit she's dating Jim, Dana realizes the truth when she accidentally pinches Jim's butt thinking it was Hank. The next day she and Cheryl have a fight over the whole situation, which leaves it up to Jim and Andy to fix the friendship between the two sisters.