Britney Spears returned to CBS’s How I Met Your Mother Monday as Abby, the silly-vulnerable receptionist with an unrequited crush on Ted (Josh Radnor). The ratings spiked with her first appearance, so she was quickly shoehorned into this new episode.

The fact that Britney’s second guest spot really didn’t work was no fault of hers. She’s not at all bad at playing clunkily-sweetly dumb. I liked the way she tried to vent her conflicted feelings of anger and love for Ted while lying in bed and staring dreamily at the ceiling: “You know what I hate most about Ted? His stupid hair … His stupid, lame, awesome hair. It’s so stupid and awesome,” she said with a cute, singsong lilt.

But the script was an awful piece of specialty construction. Abby’s reverie occurred in a bed shared with Barney (Neil Patrick Harris), who was also feeling rejected by Ted — as a friend. His and Abby’s mutual annoyance turned them both on, so they slept together.

Then they decided to pose as a couple to annoy Ted. Then Barney carried the joke too far by proposing to Abby. Then Abby suddenly thought Barney really loved her. Then, to get out of the engagement, Barney told Abby that their romance had done the trick and now a jealous Ted did love Abby. And then Abby got this crazy love-hungry Shelley Winters-like gleam in her eye, setting up the possibility for a third guest spot.

Well, that’s a lot to cram into the subplot of a 20-odd-minute show. It would have taken me less time to type out the synopsis of Dangerous Liaisons. The twists felt arbitrary and perverse, even for a so-so sitcom, which is what HIMYM is.

It’s time for Britney to move on to her next cameo project. Ugly Betty would have been a good fit, but Lindsay Lohan is already there. –Tom GliattoCBS