The merman kingdom's barrier is on the verge of shattering, and the entire clan is in imminent danger. Merman Nian Xi, to save his clan, ventures alone into the human world to find his biological father Lu Yanzhou and demand child support. Upon first arriving in the mortal world, he bravely and intelligently fights human traffickers, resolving multiple crises with his intelligence and kindness. After a paternity test, Lu Yanzhou confirms the father-son relationship. Nian Xi's mother Lian Yin overcomes numerous obstacles to come and negotiate, securing funds to repair the barrier. Nian Xi temporarily stays by his human father's side, revealing extraordinary talent and transmitting warmth with his song. Ultimately, all parties join hands to fight for the merman clan's survival hope, with the young boy bearing responsibility with his small body, interpreting bravery and dedication, while also looking forward to family reunion.