The Doctor and Gerald are now on a modern cruise ship, and the Doctor is noticeably more distant towards Gerald. While playing with some of the children on board, Gerald slips and breaks his wrist. The Doctor being the Doctor, wants to help Gerald with his wrist, but Gerald refuses the help, opting to just check it out himself. The Doctor, still skeptical as to who Gerald is, follows him and when he catches up, he recognizes a familiar yellow glow.
Cue Title Sequence: Meddle
The Doctor continues to act like he never saw what Gerald was doing and "accepts" that he just lodged the wrist back into place. From this point on, it's a one-sided buddy adventure story with the other side being a mystery as to who the hell Gerald is. Nagging one of his hairs, the Doctor does a DNA test to make sure it isn't just another version of him (tests come out negative). Next, he goes back to Australia and meets back with the Master, currently devising his plan for Spyfall. After a mind game, the Master confirms he never used the name Gerald as a disguise ("What kind of a name is 'Gerald' anyway?") and the Doctor is frustrated that he's not getting anywhere as to who Gerald is, so he whips out something he hasn't touched in well over 2,000 years: his first 500 Year Journal.
He's flowing through the journal, before stopping at a particular figure.
"It can't be..."
He's running along the ship, trying to find Gerald. When he finds him sunbathing, he finally says his final guess.
"Long time, no see...Monk."
The smile is off Gerald as the truth is revealed. The Meddling Monk has returned. The Monk then proceeds to run away, the Doctor following close. The Monk then steps into the TARDIS, closes the door, and leaves, leaving the Doctor stranded on the cruise ship.
Roll Credits: The Doctor Will Return in: End?