Planet Terra 2. A world where machines with hearts—Saber Marionettes—and humans live together. A human girl living there, Seika, commuted to school with her quiet younger sister, Lychee, a marionette. Unexpectedly, under the old school building, they encounter a naked male marionette, Ouga, who had been sleeping there. He says things like "Let's have kids!" to Seika, and tries to visit her in the night, only to instead be kissed by Lychee. Is this a gradually heating up love triangle? A new entry in the Saber world!!