When they woke up, everyone was trapped in a parallel space, which was different from the earth. It was filled with gunpowder smoke and there were many obstacles to intercept them... Almost everyone else was dead, and only the two of them were still alive. He told him in the gunpowder smoke, "I love you, please hold my hand, and let us survive together..."
Concept: They survive and save themselves in space, just to meet each other