In the wake of news about his future as an astronaut, Hibito has simply gone missing without a word to anybody - a state of affairs which might be more worrying for Mutta were it not an occurrence that he's had to deal with before while growing up with his brother.
Nevertheless, it's a worrying turn of events that naturally distracts Mutta from his all-important CAPCOM training, which in turn earns him something of a dressing down from Bold. Determined though he is to follow his dream, Hibito's whereabouts are still Mutta's primary concern no matter how much he tries to hide his worry to those around him.
As time goes by with still no word from his brother, this sense of concern spreads to Butler himself, who calls Mutta to see if he can shed any light on Hibito's whereabouts while also informing him of the full extent of the situation - even with four respected astronauts petitioning to put Hibito back on the roster for future space missions, it seems that programme manager Gates is still having none of it. As the situation gets all the more hopeless, is Hibito going to return at all? Well, he only has one episode left to do so...
Having had Space Brothers at the heart of my weekly viewing for two years now, it's sad but not entirely shocking to hear of it coming to an end (for now, at least), but beyond that this was a bit of a slow-burning episode that never quite managed to latch on to any real sense of worry about Hibito's disappearance - there was no urgency to anybody's actions for the most part, and the entire thing felt a little odd. Hopefully the series can at least end with the resolution of this story, while leaving plenty of scope for the show to return in the future - something that, much like Hibito, I most certainly hope it does.