Synopsis: Izzy is still coping with having been turned into a fish-person. The Doctor wants her to see what she's gained, not what she's lost, but it's really too much for her. She wants the Doctor to take her back in time to a point before the transformation so she can warn herself. He says it would violate a Time Lord rule.
She lashes out at the Doctor in anger. He responds by pushing her into the TARDIS pool to force her new gills to kick in. She eventually does so, but then begins to cry. After a while she rejoins the Doctor in the console room in her old clothing, now altered to fit her new body. She believes that her trust of people, and perhaps specifically the Doctor, has gotten her into this mess, and so vows never to do so again.