The Ancient Magus' Bride Vol. 7 (manga)

After mistakenly putting Elias under a sleeping spell, Chise can’t find a way to wake him up! She turns to Angie for help, and brews a potion meant to undo the spell–but the process is so exhausting, Chise ends up falling asleep herself. Upon entering a dream world, she crosses paths with the person she least expected: Cartaphilus. But something’s off–the amoral alchemist seems to have lost his threatening edge. Meanwhile, in the outside world, trouble is brewing… on a dragon-sized scale!