The gang is set into a frenzy when Gary Blauman arrives at the wedding on How I Met Your Mother Season 9 Episode 21.
Ted picks the mother up at her apartment for a date and tells her about Gary showing up on Robin's wedding day and the debate that ensued about whether or not he should be allowed to stay.
Feelings for Blauman are mixed among the friends. Marshall tells Robin he will find a space for him at the reception, while Barney shares his reason for hating Gary. Ted, Lily and others weight in on their take on the latecomer.
On the date, the mother spots her ex-boyfriend, which prompts her to tell Ted it might be too soon for her to be seeing someone new. Ted understands, but then she changes her mind.
Watch How I Met Your Mother online to see how it all transpired: