Marisa is hired by a mysterious 'Eater of Cranes' to hit a particularly tricky target. Little does she know what kind of being this 'Eater of Cranes' is, be it their species or their occupation. Even less does she know who were behind the target the 'Eater of Cranes' hired Marisa to deal with in the first place.
Spoiler alert: Despite the Len'en brand, no Mugenrines are actually sighted in this script, only spoken to. Also, this (sort of a joke) G&HS-inspired script is the end result of a headcanon about Tsurubami's post-LE1 whereabout that ballooned out of control.