New Year's Day rekindles family memories from years ago, such as John's false assumptions about the Millennium bug (Y2K) with unfortunate real effects. The arrival of third child Sophia put pressure on Tim and Heather's hippie ideas of healthy family life, which so far worked with Tyler and Samantha, who quickly demands normal modern comforts as minder Matt teaches them. Young groom Greg finds his bride Jen's tolerance for his parents meddling I constantly, however well-meaning, wears out at packing for their honeymoon, but the practical results of untested self-reliance are rather disappointing.
- Colin Hanks as Greg Short
- Betsy Brandt as Heather (Short) Hughes
- Thomas Sadoski as Matthew "Matt" Short
- Zoe Lister-Jones as Jennifer "Jen" Collins-Short
- Dan Bakkeddahl as Dr. Timothy "Tim" Hughes, M.D.
- Angelique Cabral as Colleen Brandon Ortega
- Niall Cunningham as Tyler Hughes
- Holly Barrett as Samantha "Sam" Hughes
- Giselle Eisenberg as Sophia Hughes
- James Brolin as John Bertram Short
- Dianne Wiest as Dr. Joan (Pirkle) Short
- Hunter King as Clementine Hughes