Now that Koutarou and the girls know the remnants of Vandarion’s faction are holding out on Earth, they’ll have to dig deep for a new fight on the home front. Ralgwin is patient and strategic compared to his uncle, and he’s more than prepared to play the long game. He’s already managed to get his hands on a piece of spiritual energy technology that puts him one step closer to the power of Koutarou and company, but he’s willing to play dirty to level the playing field... meaning Ruth’s in danger when a mysterious assassin appears.

Harumi and Clan take a sentimental tour of Vandarion’s special territory, swapping secrets (and more!) in hopes of better understanding their respective relationships with Koutarou. Theia and Ruth also take a trip down memory lane as they review footage and data from their trip to Earth. Shizuka and Sanae likewise reminisce about the past while doing some spring cleaning. But then it’s time to kick back and cut loose! The whole gang heads to the beach, where the girls get their chance to shine bright!

In this collection of side stories: Kiriha and Elfaria go toe-to-toe to decide who gets to take care of Koutarou when he gets sick on vacation, the story of how Yurika’s magical training went when she and Nana first met, and a chance date with Maki and Kiriha in a rather meaningful place. Then, in a very special feature, we get a glimpse into what life would be like between Clan and Koutarou if they started dating.

After the attack underground, Koutarou and company return to the surface to regroup and plan their next move. They know Ralgwin will continue to come after them as long as he still has a hold on Earth, leaving them little choice but to mount an offensive of their own in an attempt to put Vandarion’s coup to bed once and for all. Fortunately, they have a little extra help on their side with the arrival of Princess Nefilforan, known throughout all of Forthorthe for her military and martial might.

Koutarou decides to humor the haniwas and Alunaya when they take an interest in RC cars—and Clan’s determined not to be left out! After their fierce showdown, Maki’s in for a surprise encounter with an old friend. Next up, Nana and Kanae team up against their protégés in a very special game of badminton. And finally, with the big trip to Forthorthe right around the corner, the girls all scramble to get ready for their intergalactic journey. There’s so much to buy! Food, bicycle parts... And don’t forget new underwear!

Just starting high school, Koutarou is moving out on his own to take some of the burden off of his widower father. Lucky for him, he's found a room at Corona House. It has a great landlord, it's not too far from school, and best of all, it's dirt cheap. It really is perfect... except for the strange girls that keep appearing to try and take it over! But even as room 106 turns into a battlefield, Koutarou isn't willing to give up his apartment without a good fight. The invasion begins!

Koutarou and the girls prepare to chase Ralgwin back to Forthorthe, but one critical mission remains before they can leave Earth behind again—they must oversee the welcome ceremony for the next wave of intergalactic transfer students. Little do they know that someone is watching their every move from the shadows, someone with a keen interest in both Koutarou’s sword and Nalfa... Indeed, the Gray Knight is getting dangerously close the group and the truth about what happened back in the ruins. Will their rematch with him be their final showdown?