小女孩與媽媽以車為家,在她眼裡,這個特別的家,既是移動城堡也是秘密基地。她計畫邀朋友在這裡一同吹熄9歲蠟燭,不料背著媽媽籌畫的生日派對,竟成為二人衝突的起火點……。Lizon has just attended her friend Marie's birthday. The friends around the birthday cake, the candles to be blown, the wish to be made amazed her. For her ninth birthday, Lizon wants to have the same thing. A birthday with a cake, candles and her friends, at her home: in the car.