Gen saw the subtle shift, though. Most people probably wouldn't pick up on it. Most people - even those who were his friends - didn't know Senku. But the two of them had been working very closely together over the last couple of years.

He tilted his head a little. Gentle, knowing, like they're looking at real stars in the observatory, "We're not locked in this quiet car because you're bored, Senku-chan."