Xiao Mo, the MC (Shou) runs a second-hand/ recycling shop before the apocalypse. One day, he sees Xue Li Hong, our ML, sleeping on the bench. Worried for him (ML was a kid then), he feeds him.
From there on, a series of unfortunate events happen as Xiao Mo gets stuck with an almost inhumane and cold system, and tries his best to complete the missions. The ML tags along with Xiao Mo due to the little act of kindness from the very beginning, and helps our MC with his physical prowess and his magical backpack full of tools. As they stick together to clear missions and survive through the apocalypse, feelings slowly develop.

The MC isn't your cold-hearted OP protagonist; he's quite imperfect actually, but he does have some cool abilities. He is a little Gary Sue in the sense that he tries to see the goodness in everyone, but he acknowledges this and tries his best to curb it. Overall, he's a little too s*upid, a little too kind, and a little too trusting. Luckily for him though, he has the ML to balance it out. The ML, on the other hand, is your typical cold-faced and analytical OP ML that is indifferent to everyone but the MC. The both of them complement each other very well, and with the other teammates that join them in the future, they make a very holistic team.