Jocasta Nu's cache, a training facility for a new generation of Jedi, was established by Chief Librarian Jocasta Nu and her assistant Gar. This occurred after the implementation of Order 66, and the rise of the Galactic Empire. The school was located on a remote, concealed planet. Inside the school were several holocrons containing Nu's teachings and knowledge, along with statues, artifacts, and devices resembling Marksman-H training remote. During the early years of the Great Jedi Purge, Nu returned to Coruscant aboard a golden-plated Delta-7B Aethersprite-class light interceptor with her droid Beetoo. Her mission was to find a holocron containing a list of all Force-sensitive children catalogued before Order 66. Darth Vader killed Nu upon her return to Coruscant, preventing her from training new Jedi and rebuilding the Jedi Order.
Years later, Gar, feeling too old to protect the enclave, triggered an explosion to seal the entrance, entombing himself and the school. Around 6 ABY during the New Republic Era, Jedi Knight Luke Skywalker, Vader's son, discovered the school while trying to restore the Jedi Order. Later, while exploring an old Jedi outpost on Elphrona with his nephew Ben Solo and Lor San Tekka, Skywalker commented that the Jedi artifacts on Elphrona might be even more impressive than those in Nu's school.
The first appearance of Jocasta Nu's cache was in Darth Vader (2017) 6, a canon comic book from 2017 written by Charles Soule and with art by Giuseppe Camuncoli.