CBS

Can a single person be friends with a married person of the opposite sex? According to this week's How I Met Your Mother, probably not. The episode is framed around Ted's burgeoning friendship with Zoey, and whether or not theirs is an appropriate relationship, considering the fact that Ted finds her attractive and that she is also married to Kyle MacLachlan's "The Captain." After receiving a lecture from Lily on the "dont's" of a single/married friendship (no candles, no sharing food, and no lying to the spouse), Ted spends the remainder of the episode in a state of moral paranoia, and Robin and Marshall decide to test the societal restriction by going out to dinner alone.

The episode takes an unfortunate turn, though, when Marshall tries to explain it all through Barney's "Mermaid Theory," which strays from the simple premise that men and women can't be friends, especially when one is married (which we know all too well thanks to Nora, Rob, Harry, and Sally). The theory is that men will always, eventually, come to find women they interact with attractive—from friends to secretaries. It seemed like just an excuse to dress the cast up in ridiculous sailor and manatee costumes.

And yet in spite of the failure of the episode to sell "The Mermaid Theory" as some sort of truism, it was redeemed by a terrifically campy performance by Kyle MacLachlan, and an effective gag involving Lily, Barney, and narrator Ted. Sometimes it's easy to forget that the entirety of How I Met Your Mother's narrative is framed by Ted's recollection of events 20 years in the past. For six seasons we've been given a fairly seamless tale, leading the audience to suspect either that narrator Ted wrote meticulous accounts of his youth in Manhattan that he studies before each session with his children, or that he must be the greatest storyteller of all time.

This week, however, after a few false starts, narrator Ted admits that he can't remember the specifics of why Lily and Barney were fighting. In his attempt to rework the story, Lily and Barney break the fourth wall and turn to look directly at the camera directly with confusion and annoyance. Even Ted's always skeptical-looking children smile briefly. It's a small but significant gesture to the audience that the writers and actors are with us: 124 episodes is a long time to stick with a story that doesn't seem close to finishing. But perhaps it's also an acknowledgment that the conclusion of how Ted eventually meets his wife almost beside the point.