Ted and Robin are surprised to run into Barney when they volunteer at a homeless shelter on Thanksgiving.
When the gang views a tape from Barney's ex-girlfriend, everyone must share their most embarrassing moment in order to get him to tell the full story about the tape.
When Ted attends his mother's wedding, he is disturbed by her overly affectionate relationship with her fiance.
Marshall bequeaths a "slap bet" slap to Ted and Robin; Lily's estranged father (Chris Elliott) visits for Thanksgiving.
Marshall, Lily, Robin and Kevin celebrate Valentine's Day with a weekend in Vermont; Barney meets his match.