Pi Pi accidentally injures Da Jun, a thief who attempts to steal Tao Tao's backpack. Da Jun extorts the Guo family for his injury and threatens to report the incident to the police. Thinking that his parents might abandon Pi Pi, Tao Tao hides his beloved pet dog but returns to find Pi Pi missing. 涛涛对爱犬皮皮疼爱有加。然而，随着涛涛的成长，他能陪伴皮皮的时间变少了。一日，皮皮咬伤了企图偷涛涛背包的大君。大君要求天价赔偿金不果，威胁要报警。涛涛误以为父母要舍弃皮皮，便将皮皮藏在垃圾场。隔天，涛涛回到垃圾场才发现皮皮不知所踪。

A boy appears lost claims to be Pi Pi and follows Tao Tao around. After the boy speaks with a dog and saves Uncle Robin from danger, Tao Tao couldn't help but believe that the boy is Pi Pi. Tao Tao hides the boy at home while trying to figure out the truth. 一名行为像狗的小孩（凯文）自称是皮皮，涛涛原以为他在胡闹，但凯文却听得懂小狗Batman说的话，还因此救了Batman的饲主Robin。涛涛把凯文带回家，发现他对家中格局了若指掌，一举一动也像极了皮皮，才相信凯文就是皮皮，并偷偷收留了他。

Tao Tao coaches Pi Pi to behave more human-like. Tao's mum learns that Pi Pi is lost and scolds him. Tao Tao in turn, blames his parents for having the intention to send Pi Pi away and is shocked to find out that it was all a mistake. Tao Tao's parents discover Kai Wen. 涛涛训练凯文改掉狗的习性。两人在公园遇到少女莉莉和她的狗阿布，凯文把阿布的心声告诉了莉莉。涛妈得知涛涛把皮皮给弄丢了，责怪他。涛涛委屈反怪爸妈打算遗弃皮皮，这才惊觉一切原来只是误会一场。而涛爸妈也发现了躲在家中的凯文。

Robin shows up to show his gratitude and grabs the chance to get Robin to pretend to be Kai Wen's grandfather. Robin shares with Tao Tao, the strange phenomenon that he witnessed and suspects that Kai Wen and Pi Pi's souls have been swapped. Meanwhile, Kai Wen's parents chanced upon a strange dog. Robin上门感谢涛涛救了他，涛涛顺水推舟让Robin配合，谎称凯文是他的孙子，并拜托涛爸妈帮忙照顾凯文一阵子。Robin告诉涛涛他目睹一件怪事，怀疑凯文和皮皮交换了灵魂。另一边厢，凯文父母发现家门前有只狗（皮皮身体，凯文灵魂）在等候。

Tao Tao's parents are very hospitable and welcoming to Kai Wen. Li Li says she has posted about Kai Wen's ability online and registered an account under the name Wang Xing Ren. The posts go viral, and the account gains overnight popularity, drawing a lot of attention, including Da Jun's. 涛爸和涛妈对凯文关怀备至，凯文体会到当小孩的幸福，开始纠结未来还要不要继续当狗。与此同时，莉莉传来简讯，原来她把凯文帮狗狗的经过写在了网上，还替凯文注册了名为「汪星人」的账号。凯文一夜之间爆红，也引来了大君的关注。

Kai Wen gets invited by animal shelters to be an interpreter for. Tao Tao accepts endorsement offers in order to help Kai Wen. He focuses on managing the Wang Xing Ren account, and starts to have less time for Kai Wen again. Kai Wen is found by his parents, who were tipped off by Da Jun. 凯文受邀到流浪动物中心帮流浪狗做「翻译」，向涛涛透露他希望能改善流浪狗的生活环境。涛涛为了帮凯文达成愿望，接了很多业配，专注经营「汪星人」账号。凯文有感再次被涛涛忽略，和他吵了一架，到公园散心，却遇到了大君带来的凯文父母。

Kai Wen's parents are worried when their son does not recognize them. Pi Pi learns that Kai Wen's dog passed away recently and was upset when his mom threw Rainbow's collar away. Pi Pi gets taken to Kai Wen's home and manages to get in touch with Tao Tao, who reminds Pi Pi to live as Kai Wen. 文爸妈见凯文认不得他们，晴天霹雳。凯文从他们口中得知，他因爱犬Rainbow去世而一蹶不振，并为了找回Rainbow的项圈一去不返。凯文联系上涛涛，两人和好如初，涛涛要凯文暂以「凯文」的身份生活。与此同时，涛涛担心「皮皮」的安危。

Pi Pi learns to be independent and finds out that a dog came to Kai Wen's parents. The dog was later sent away. Tao Tao and Kai Wen goes in search of news of the dog. They met Xiao Mei and her dog Tiger, who told Kai Wen that Xiao Mei's grandmother is unwell. Tao Tao receives a photo of a familiar dog.

Da Jun plans to defame Tao Tao and Kai Wen using the dog he adopted. His accomplice Xiao Mei changes her mind and did not want to help Da Jun after her grandmother was diagnosed with intestinal cancer. Li Li calls to inform Tao Tao about the defamation on Wang Xing Ren's account. 领养皮皮的人原来是大君，他以此威胁涛涛和凯文出来前面。原为大君同伙的小梅带外婆到医院检查，外婆被诊断患上了大肠癌。小梅感激凯文的帮忙，决定不再和大君合作。涛涛收到莉莉的电话，才发现「汪星人」的账号被数以百计的谩骂留言给淹没了。

Da Jun's plan succeeds as dog lovers believe that Tao Tao and Kai Wen are scammers. Kai Wen's parents confront the Guo family when they think Tao Tao badly influenced their son. Xiao Mei records a video to clear Tao Tao and Kai Wen's name, exposing Da Jun's motive. 大君恶意剪辑了和涛涛、凯文会面的录影，营造出他们是骗子的错觉，还创立了众筹户口，利用皮皮卖惨敛财。文爸妈来涛涛家理论，认为涛涛带坏了凯文，涛爸妈这才知道凯文不是Robin的孙子。小梅不忍看涛涛和凯文受责，拍影片还原真相反击大君。

Tao Tao and Kai Wen learns that Da Jun is Robin's grandson. Da Jun blames Robin for the death of is pet dog, Man Tou. Robin finds an old video of Man Tou which Kai Wen translated for Da Jun. Tao Tao and Kai Wen, together with Pi Pi, attempts to undo the body swap. 原来Robin是大君的爷爷，大君小时候因Robin的拾荒习惯而受到霸凌，也把爱犬馒头的死归咎于Robin，从此性情大变。凯文从Robin播放的旧影片中，听见了馒头的遗言，解开了大君的心结。涛妈暗地给钱大君要回皮皮。涛涛一伙人带凯文和皮皮回到垃圾场企图让灵魂对调回来却失败了。

Robin concludes that the appearance of a rainbow is crucial to their success. When the next rainy day comes, Kai Wen shows up too late to do anything. He explains to Tao Tao that he no longer wants to return to his dog body. As a turn of events, Kai Wen learns that his family is relocating overseas. Robin猜测彩虹是灵魂对调的关键因素，大家只好等待下一个雨天的到来。然而，等雨天到来时，凯文却迟迟不出现。尔后，凯文向涛涛坦白他想继续以人类的身份陪在涛涛身边。没想到，凯文却被父母告知他们一家即将移民到国外。

Da Jun and Robin reconcile and Xiao Mei's grandmother gets discharged from the hospital. Kai Wen is on his way to the airport when he spots a rainbow. Kai Wen rushes to the meeting place and met with Tao Tao and Pi Pi. They hold their breath as they wait for the transformation to take place... 大君和Robin和好，小梅外婆也顺利出院。凯文随父母前往机场的路上，见空中出现了彩虹，凯文赶到垃圾场，对涛涛说出心底话后，终于成功和皮皮把灵魂对调回来。涛涛带着「真皮皮」回到家，似乎能听见皮皮说的话。时过境迁，皮皮成为了受欢迎的网红狗。