Leslie ( Amy Poehler ) throw her annual " Galentine 's Day " party for her female friends , celebrated the day before Valentine 's Day . She ask her mother , Marlene ( Pamela Reed ) , to tell the story about how she fell in love with a lifeguard that saved her from drowning in 1968 , but the two had to break it off over objections from Marlene 's parents . Leslie later tell the story to Justin ( Justin Theroux ) , who is amazed by the tale and want to unite the two . He successfully track down Marlene 's old flame , Frank Beckerson ( John Larroquette ) , and convince Leslie to go with him to Illinois and reunite the two on Valentine 's Day at the Senior Center Valentine 's Dance , which the parks department oversee .