Minecraft: The Mountain — Max Brooks

In the thrilling sequel to the New York Times bestselling novel Minecraft: The Island, a stranded hero stumbles upon another castaway -- and discovers that teamwork might just be the secret to survival.
 
Wandering a vast, icy tundra, the explorer has never felt more alone. Is there anything out here? Did I do the right thing by leaving the safety of my island? Should I give up and go back? So many questions, and no time to ponder -- not when dark is falling and dangerous mobs are on the horizon.
 
Gurgling zombies and snarling wolves lurk in the night, and they're closing in. With nowhere to hide, the lone traveler flees up a mountain, trapped and out of options . . . until a mysterious figure arrives, fighting off the horde singlehandedly. The unexpected savior is Summer, a fellow castaway and master of survival in these frozen wastes.
 
Excited to find another person in this strange, blocky world, the explorer teams up with Summer, whose impressive mountain fortress as a safe haven . . . for now. But teamwork is a new skill for two people used to working alone. If they want to make it home, they will have to learn to work together -- or risk losing everything.