Some time after the Mousekewitz's have settled in America, they find that they are still having problems with the threat of cats. That makes them eager to try another home out in the west, where they are promised that mice and cats live in peace. Unfortunately, the one making this claim is an oily con artist named Cat R. Waul who is intent on his own sinister plan. Unaware of this, the Mousekewitz's begin their journey west, while their true cat friend, Tiger, follows intent on following his girlfriend gone in the same direction.
「夏目友人帐」第7季动画制作决定。
三年前，云岚宗少宗主纳兰嫣然贸然退婚，倍感耻辱的萧炎遂与纳兰嫣然定下三年之约。为了这个约定，萧炎一直修炼不息，从魔兽山脉到塔戈尔沙漠的历练，从炼丹到吞噬异火的焚身之痛，都为证明那句话：“三十年河东，三十年河西，莫欺少年穷”。如今，萧家男儿必将迎难而上，永不退缩，萧炎的成长之路仍在继续……
