What happens when Harry meets a different student before boarding the Express? And why is this student so different to other wizards?

The Tardis has a track record when it comes to inadvertently ending up in the wrong universe. But what happens when the Doctor, Yaz, and Dan end up crossing through the barriers separating realities, right into the path of a displaced Kamala Khan? Doctor Who/Marvel Cinematic Universe Crossover Set immediately after #MsMarvel