To date, there are seventeen volumes in the True Tenchi Muyo! GXP series of light novels. Volume eleven was written by Masaki Kajishima to augment the second half of the anime. It is unavailable outside of Japan.
The current head of the Kuramitsu family is in bad health. Already, members of the Seniwa dynasty are flocking to their capital planet to pay respects and weigh in on who will succeed them.
Mihoshi found time to visit as well, and is amazed when she discovers Washu arriving in adult form, dressed in funeral attire. This is the first time in many centuries that any of the Kuramitsu lineage have seen her in person.
Meanwhile, Airi is catching up with Seto about the recent battle between the Kamidake and members of the Daruma faction. They are both convinced that Kiriko, given her connections to the Masaki bloodline, could use this opportunity to get some upgrades and help the rest of the team survive the next encounter intact.
Seto thinks to ask Airi to handle this directly, as adopting Kiriko into her side of the family is a good strategy.
Unbeknownst to either of them, this only fuels the fires of another conflict between the Amane and Kiriko clubs.
Following through on some planned upgrades, the Kamidake and Fuku are greeted by Royal Trees as Seto and her team get to work. Her own ship, the Mikagami, is berthed near the top layers of the Jurain tree Tenju. It is a place off limits to anyone outside of the upper echelons of the Jurain establishment.
Seina and the others are given a tour of some of the rural spaces on Jurai. He is immediately reminded of home. Yuzaki prevents Seina from straying off course, but Amane gets left behind. Meanwhile, judging by a large selection of packs and other accessories, Kanemitsu is planning with Seina's help to scale the giant tree.
After some other antics, Seina and Ringo find a place to crash for the night, with Fuku accompanying them.
We last see Kanemitsu climbing Tenju with the girls. They pause when they misplace Neiju, but find that she has rejoined Nene and Karen elsewhere.
Elsewhere, Daruma beholds the newest battleship added to his fleet. It resembles a treasure ship more than something combat worthy, and might prove useful in the next volume.
Seina reconnects with members of his team, and discovers that Kiriko has already received an incredible suite of bio-upgrades due to being officially inducted into the Masaki Jurai lineage.