As anyone who is remotely interested in the series the eighth season finale of How I Met Your Mother aired last night, and as anyone who is remotely interested in the series has already seen or heard, there was a surprise ending—which we will touch on—but this post is more general in its scope.
Last week, after the penultimate episode, we knew in advance that the finale would not be the Barney-Robin wedding (where it has already been revealed Ted first sees the woman who becomes the eponymous mother). In the eighth-season opener they teased us with a "flash-forward" scene where it's after the wedding and Ted is waiting at the train station and the woman with the yellow umbrella (whom we know from much earlier in the series is the mother) stands nearby, her face obscured by that item (below).
At that point (back in September) this eighth was to be the final season, so the groundwork laid there clearly suggested in the finale it would close with the continuation of that scene, presumably with Ted and the woman under the umbrella glancing over at each other. We'd get a shot of the mother's face under the umbrella, they'd share a smile as some uplifting song plays underneath, then cut to the kids in the future on the couch wiping a tear away as narrator Ted caps it with the obvious but appropriate, "That's how I met your mother." Roll credits.


