在第三季故事的5年后，Paul（马丁·弗瑞曼 Martin Freeman 饰）和Ally（黛西·海格达 Daisy Haggard 饰）面临着最大的养育挑战。18岁的Luke（奥斯卡·肯尼迪 Oscar Kennedy 饰）在圣诞晚餐上抛出了一个炸弹消息，这将永远改变每个人的生活。16岁的Ava（佐伊·雅典娜 Zoë Athena 饰）不再处于Luke的阴影下，当遇到魅力非凡的Holly（杰西·威廉姆斯 Jessie Williams 饰）时，她经历了自己的爆炸性时刻，并立即爱上了对方。Paul和Ally在面对这些最新的养育挑战时，不断尝试，失败，再尝试。

　　讲述在这快节奏的世界中，三姐妹Hannah﹑Nina及Rose皆是离婚律师，Hannah与Nina在竞争对手的公司中领导离婚及家庭法的律师，只有三妹Rose还在找寻自己的位置。同时，三姐妹及母亲因为那缺席了30年的父亲/丈夫Oscar重新出现，令她们的生活面临瓦解。

　　An uplifting and heartwarming story about finding the magic of Christmas, no matter where you might be, This Is Christmas follows Adam (Alfred Enoch) and Emma (Kaya Scodelario) as they make their daily commute from the picture-perfect village of Langton to London for work. Every day they share their journey with the same characters, but they all keep themselves to themselves. But then one day, in the build-up to Christmas, Adam breaks the unwritten rule of travel and starts talking to the strangers on the train, inviting the whole carriage to hold their own Christmas party.