To date, there are seventeen volumes in the True Tenchi Muyo! GXP series of light novels. Volume 4 was written by Masaki Kajishima to augment the events of episode 7 in the anime. It is unavailable outside of Japan.
Seina moves in with the girls. Seiryo is still causing havoc for the Academy in his belligerence toward Seina. After a failed shopping excursion with the girls, they relax at a café in Naashisu. Seina upsets Airi by calling her 'granny'.
When the group returns to the house, it appears that Seto's scouts have been appointed as maids for security reasons.
Antics ensue. While Seina detaches from the group, he bumps into Miki who bears a resemblance to a protagonist from Dual! They escape into the depths of a forest surrounding the Academy grounds, on the premise that she is on a date with him to her secret spot. He meets her father, whom she asks Seina to take care of while she is away.
NB tries to transform into Miki but fails. Seina learns that Miki and the other people she had been working with were all murdered in a pirate attack. The girls prepare a second round of bio-enhancement to take his mind off it.