Everything must have a beginning. (すべてには始まりがある。 Subete ni wa hajimari ga aru): is the 4th episode of The Ancient Magus Bride anime.
Chise wakes up in Elias's lap after having passed out at the Dragons' Aerie and dreamt about a strange girl petting her cat just before a Matthew walked into the room. Chise and Elias is visited by Jasper who welcomes them to Ulthar. Once there, the company meets up with another cat and the current King of Cats before following them to a lake near the town where Chise learns about the town's past before being thrown into the lake by a strange woman.
While Chise is in the lake, she's approached by Mina who explains both her and her husband's situation to the apprentice before Chise is woken up by Elias. They await until nighttime to prepare Chise for her of task of cleansing the lake with the help of various materials and an Ariel. She is interrupted however by the woman from earlier and a Sorcerer called Renfred, revealing to Chise about her fate as a Sleigh Beggy.