Shy 14-year-old Duncan goes on summer vacation with his mother, her overbearing boyfriend, and her boyfriend's daughter. Having a rough time fitting in, Duncan finds an unexpected friend in Owen, manager of the Water Wizz water park.
| Actor | Role |
|---|---|
 Liam JamesDuncan | Duncan |
 Steve CarellTrent Ramsey | Trent Ramsey |
 Toni CollettePam | Pam |
 AnnaSophia RobbSusanna Thompson | Susanna Thompson |
 Sam RockwellOwen | Owen |
 Allison JanneyBetty Thompson | Betty Thompson |
 Maya RudolphCaitlyn | Caitlyn |
 Amanda PeetJoan | Joan |
 Rob CorddryKip | Kip |
 Nat FaxonRoddy | Roddy |
 Jim RashLewis | Lewis |
 Zoe LevinSteph | Steph |
 River AlexanderPeter Thompson | Peter Thompson |
 Adam RieglerNiel | Niel |
| JJeremy WeaverJason | Jason |
 Robert CapronKyle | Kyle |
| RRodney LodgeMalcolm | Malcolm |
 Devon WerdenLaura | Laura |
 Ava Deluca-VerleyKaty | Katy |
 Jake PickingChad | Chad |
 Jeff RyanCharlie | Charlie |
 Andria BlackmanBeautiful Woman | Beautiful Woman |
 Aingea VenutoSunbathing Girl | Sunbathing Girl |
 Emily PettaTeen's Mother | Teen's Mother |