After traveling to Uriel via tesseract they decide to fly on Mrs. Whatsit's back after she transforms into a mythical dragon-like creature. The plan is to go to the happy medium to use her globe to find out where their father is and save him.
The happy medium used her globe to help the group find their father
I have found your father.
When they tesser to Camazots everyone gets gifts Calvin gets the gift of speech, Charles gets the gift of controlling his arrogance, and Meg gets the gift of her faults and Mrs. Whos's glasses
Meg I give you the gift of your faults
Charles is a pretty smart but he relied too much on his skill and it cost him. After a lot of convincing from the man with the red eyes Charles finally went under IT's control thinking he could go into him defeat him and come back out, now it's a rescue mission for not just their dad, but for Charles too
Come Charles Wallace let me show you the way
After using the happy medium's globe to find out where their father is Meg goes and gets her father out of the chamber using the glasses Mrs Who gave her on Camazots
Father I found you!!!
After tessering away from IT, and leaving Charles with IT Meg is hurt and needs healing, but they meet a weird character named Aunt Beast who heals Meg and sets them back on their case to save Charles and stop IT.