Gamora arrives on Torndune-- a once-lush planet that has been strip-mined for the power source beneath its surface-- with a mission: collect the heart of the planet. Her adopted sister Nebula is in hot pursuit, determined to claim the planet's heart and shame her sister. Each allies herself with a faction on the planet in order to gain access to the massive diggers capable of drilling to the center of the planet. It's a competition they can never win... unless they learn to trust each other.