The lost child Momo is gone.

The Lost Child takes the disappearance of Yang Yuan's nine-year-old son, Yang Mo, as a clue and involves different secrets of the residents living here. These seemingly unrelated people, overlapping in different time and space, start again at this moment. ...

The lost child Momo is gone.

On the morning of winter solstice, Yang Yuan, who stayed up all night writing, was awakened by the alarm clock. As soon as she woke up, she heard his wife Fang Tao lecturing Yang Mo for her poor homework. Yang Yuan woke himself up. After washing in a hurry, he was ready to go out and send Yang Mo to school, while Yang Yuan took a gift and gave it to Xu, who had been tutoring Yang Mo.

Yang Yuan then carried Yang Mo's schoolbag, started the car first, drove to the unit building of Qinglan Garden, and waited for Yang Mo downstairs, while Yang Mo lingered upstairs for a long time, only slowly went downstairs at the urging of Fang Tao. Yang Yuan waited downstairs for a long time, but didn't wait until Yang Mo came downstairs. Seeing that he was going to be late for school, he had to call Fang Tao to urge him.

Fang Tao answered the phone and realized that Yang Mo didn't go downstairs, but she saw Yang Mo go downstairs with her own eyes, so she didn't believe that Yang Mo hadn't gone downstairs yet. Fang Tao looked down from upstairs and Yang Yuan looked up from downstairs, but didn't see Yang Mo, so he searched the whole house, but still didn't see Yang Mo. Fang Tao and Yang Yuan blamed each other and looked for Yang Mo everywhere. They suspected that Yang Mo had gone to a neighbor's house, so they went to Xu's house first. There is no one at home. Fang Tao immediately knocked on the neighbor across the hall, but the other party didn't see Yang Mo, and she was too busy to help them find Yang Mo. Yang Yuan and Fang Tao knocked on every door in the apartment building, but no one saw Yang Mo, so they were in a hurry.

Since Yang Mo mysteriously disappeared in the corridor, Yang Yuan and Fang Tao began to look for their children. After his son disappeared, Yang Yuan's mood completely collapsed. He usually submit to humiliation, but in the face of his son's affairs.

Yuan Wu intends to hide his father's body and continue to live on his father's pension. Therefore, when Zhang Ye came to investigate, Yuan Wu was very flustered. He is afraid that Zhang Ye will find out his secret. And Yuan Wu also met momo in this secret passage. Momo was scared to pee when she saw Yuan Wu's father's body. Yuan Wu was afraid Momo would tell his secret and hid him in a crack in the wall.

DOG and Xu agreed to go to the northern suburbs together. DOG came out from home, first hid in the hsu family, and then they went to play together. However, when Momo went to Wynn's house, he accidentally found a secret passage in the closet. He used to meet Yuan Wu's father and was stunned by Yuan Wu, so Wynn didn't find Momo when he went to the northern suburbs to look for him.

But after Zhang Ye left, Yuan Wu went to the secret room to find DOG, and there was no DOG.