With Meg's injury from last episode, she is headed to the Medical City of Aquamarine to be treated. Jack, who is the Sage of Life, made a promise to help heal Meg. Though the doctor explaining that Faust came to them before Jack was around, asking to save Meg. We had the sense of it, but you really come to realize that Faust looks at Meg like a daughter.
It was also nice to see Mary & mom doing a lot better now. Though the café that Mary's grandfather runs, Jack's daughter Coco. Honestly, there is a good amount in this episode that we can see similarities between Faust & Jack. He definitely seems passionate about his work. Though learning about Coco's mom is sad. I highly expect that Jack to this day is torn that he couldn't save his life. I do wonder his fear is if this happens to Coco. Which would make sense why he is working so hard.
Jack ultimately wants Meg's help because she can aid him to save those suffering from stage V of magic contamination as she's saving the Lapis Spirit Tree will help. Meg's eyes are very unnatural. His theory of the incident that Meg almost died affected her and curse her. Though there is probably more we are missing. I do wonder if him seeing Meg cursed and her being the same age as his daughter, I wonder if it will get him to try to not worry about his daughter as much. We can see how concerned Coco is of her father overworking herself.