Kai is a black fox, who joined Star Fox a while back. After the adventures on Dinosaur Planet, Krystal had also become a member of Star Fox. During that time, she and Kai had started a relationship, and were soon engaged. But he left her without warning, and since then Krystal had developed a hatred for him. Kai had left the team and took his own path.
But now a special mission has come up, and Fox knows they need Kai's help. On a planet known as Rankin, Wolf has been developing some sort of weapon. It's clear that he isn't working alone, but it isn't clear who's helping him.
So Fox contacts Kai, who is reluctant at first. But finally, he's coaxed into helping the team, and arrives on their ship late one night. He goes to his old room, which is connected to Krystal's. When the morning comes, Krystal awakens to the sound of the shower in the room next door, and knows that means one thing; Kai's back. How can she stand this mission if the one she hated was back?