"Rally," the 18th episode of How I Met Your Mother's final season, acts as a recovery episode where the gang attempts to revive a hungover Barney before his wedding, utilizing creative flash-forwards to show them breaking their vows to never drink again. Critics highlighted the episode's fast-paced humor and effective use of the classic group dynamic to offset the slower pace of the overall final season. Read the full recap at TV Fanatic . How I Met Your Mother Season 9 Episode 18 Recap: Rally