圣诞老人斯科特（蒂姆·艾伦 Tim Allen 饰）决定举办一场盛大的家庭聚会，这一次，他请来了妻子卡罗尔（伊丽莎白·米切尔 Elizabeth Mitchell 饰）的父母，好让他们一家人团聚。与此同时，卡罗尔的腹中已经怀上了斯科特的骨肉，他正在非常激动的情绪之中等待着这个小生命降临。
那边厢，克隆圣诞老人杰克（马丁·肖特 Martin Short 饰）一直没有放弃过取代斯科特的幻想，他决定趁着这个节骨眼，让他的阴谋卷土重来。斯科特带领儿子查理（艾力克·洛伊德 Eric Lloyd 饰）、前妻劳拉（温迪·古逊 Wendy Crewson 饰）、矮人首领柯蒂斯（史宾塞·布瑞斯林 Spencer Breslin 饰）等朋友们，一起对抗杰克的诡计。
Lewis returns to Oxford after several years absence and is reluctantly assigned by his new boss, DCS Innocent, to the murder of an Oxford mathematics student who was shot while participating in a sleep study. The key-code used to access the sleep lab was assigned to a fellow maths student, Daniel Griffin, but Daniel's math tutor has provided him with an alibi. Daniel is a maladjusted young man who will soon inherit his father's automotive empire. He is disruptive and has no respect for his uncle who now heads the company. The future of the company however rests on an impending deal with Japanese investors who insist that family unity is all important at this time. When two other murder occurs, Lewis must decipher a cryptic clue left in an old case file by his former boss, Chief Inspector Morse.
