Megan's world is turned upside down when she hears her calm life with her little brother and single mum is about to change. She hears she's soon to have a stepfather and a stepsister. Megan thinks they're a bit weird and is determined to stop the wedding. She discovers they're actually even stranger than she thought - they're from another planet.

Jack Jr, Miles Jr and the whole gang are back for one last wine-soaked journey prompted by the mysterious "Sommelier." Joined this time by Puck, a fan of The Napa Boys comics, the group will learn about love, loss, friendship and viticulture.