WARNING: The following contains spoilers for Link Click Episode 5, now streaming on Funimation.
After finding out in Episode 4 of Link Click that he will watch three people die before his eyes, Cheng Xiaoshi knew he couldn't stand by and do nothing. But time travel is tricky. He can't very well explain to Hongbin, Liu Meng, and his mother that an earthquake is going to kill them without telling them how he knows. It would cause a mass panic and possibly do more harm than good. And changing the past to save these three people will irrevocably change the future and their present timelines.
It's a bitter pill for Cheng Xiaoshi to swallow -- so bitter that he can't actually it, which leads him to plea with Lu Guang to let him save one person's life in Episode 5.
Cheng Xiaoshi tries to warn Hongbin and Liu Meng that an earthquake will strike at 8:30 PM but neither one believes him. He even causes discord among their family when Hongbin's mother starts berating the two for abandoning her for the city. With so many people interrogating and watching him, Cheng Xiaoshi's world starts spinning and his breath quickens. He blurts out a lie that he learned it from a magazine and leaves. Cheng Xiaoshi knows he can't save everyone but he begs Lu Guang, voice breaking, to let him save at least one person: Chen Xiao's mother. Hearing how desperate he sounds, Lu Guang agrees to help him.
With only 25 minutes until the earthquake hits, Cheng Xiaoshi arrives home and tells Chen Xiao's mother about the incoming disaster and to hide in the dining room where, according to Lu Guang, Chen Xiao of the present timeline was saved. The two pack as much as they can with five minutes to spare and crouch underneath the table, waiting. Suddenly, Chen Xiao's mother is about to crawl out to grab her son's camera but Cheng Xiaoshi stops her and goes instead.
The ground rumbles and splits apart, the roof above them collapses and the support beams start buckling. Cheng Xiaoshi is still not under the table and his mother cries out for him. As the whole world falls apart, Lu Guang closes his eyes and Cheng Xiaoshi races for cover. In a split second, everything turns dark.
The first thing Cheng Xiaoshi registers is how dark everything is. He's buried under rubble and the only reason he hasn't been killed is because his mother, in the midst of all of that chaos, protected him with her body. Chen Xiao's mother holds his hand just as Cheng Xiaoshi's own mother held his when he was a child and terrified of the dark. She tries to reassure him, telling him she's a little tired and wants to rest but Cheng Xiaoshi's eyes fill up with tears. He knows that despite all of his efforts, she is going to die.
Chen Xiao's mother starts singing a lullaby and Cheng Xiaoshi thinks back to when his mother did the same. When she falls silent, Cheng Xiaoshi curls up and sobs. His pain is palpable as he cries out, terrified of the dark and being alone. When they're finally rescued, the paramedics put Cheng Xiaoshi on a stretcher and drag away his father, who had arrived too late, leaving his mother's body still trapped under the cement.
At the end, Link Click shares Chen Xiao's last words to Hongbin, Liu Meng, and his mother. With Hongbin, he reminisces about the past where they used to play together as a team and thanks the captain for always including him. With Liu Meng, he looks forward to the future where she had planned to move to the city. And with his mother, Chen Xiao sings the very same lullaby that she once sang to him when he was a child and that he's now singing to his own son.
Before Cheng Xiaoshi time-traveled back to 2008, he learned that Chen Xiao had an argument with his mother. Their relationship wasn't perfect but he can see how she only wanted the very best for him. Her disapproval of her son heading off to the city was only because she was reluctant to let go of her child. Ultimately all she wanted to do was support Chen Xiao and his father to follow their dreams -- even if that means saying goodbye.