S2·E71 Farewell, Koharu-chan!?

Elza tells Koharu that the Venus Ark will be leaving Japan for a tour. Meanwhile, Yume, Rola, and Mahiru, whose exchange programmes aboard the Venus Ark are scheduled to end as a result, assume that they will end up having to part ways with Koharu once again, becoming worried when they can't find her aboard the ship before it departs.