After the events of Turtles Forever, the team has been trying to take things easy in the aftermath. But of course nothing ever goes right for them, so when Don's latest invention backfires, the brothers find themselves in a new world. Stranded with no way out, the brothers must stick together to survive, alongside team RWBY as they're caught in this world's darkest moment.

The Vytal Festival. A celebration of the peace of Remnant. But for the students and teachers of Beacon, it's the backdrop for sinister plots and growing threats. And Earth isn't doing much better. Karai is still trying to figure everything out, but she knows one thing. These bad guys are going down. Ninja style.

After learning the truth about her past, Karai escapes to Remnant and enrolls at Beacon. Now for the first time in her life, she's a teammate, a friend, perhaps even a sister. But something sinister is happening in Vale. And Karai is going to learn that the past isn't easy to run from. . .