The year is 2543. You are the last cactus on Earth. You live in the scorching deserts of the Rocky Mountains in what used to be Alberta, Canada. The heat is nearly unbearable and wildfires are common. The rest of your fellow cacti have moved to a more temperate climate ... on Mars. They have sent a final spaceship to transport you there. Reaching it won’t be easy. Water has become Earth’s most precious resource, and although you are a cactus, you need every drop. You’ll collect the water as you move through the canyons on your way to rendezvous with your rocket. Every so often, you’ll even find a bucket of water, and you’ll be able rest for the night. But watch out for the humans. The few that remain after World War XII think they need the water even more than you. And they’ll do anything to protect it.