Changes (comic story)

Summary
Peri Brown and Frobisher are rummaging through a storage room in the TARDIS and Peri is so much taken aback by the cultural treasures she discovers that doesn't pay attention when the Doctor reports that there is an intruder aboard the TARDIS. Peri and Frobisher decide to explore the TARDIS some more, while the Doctor investigates the intruder. Ultimately, the Doctor learns the intruder is a shape-shifter, and the job of apprehending the creature is made more difficult when it creates duplicates of first himself, and then Peri. Ultimately, it takes the efforts of another shape-shifter -- Frobisher -- to defeat the creature.

Characters

 * The Doctor
 * Frobisher
 * Peri Brown
 * Peri displays a knowledge of art and culture, being able to identify unknown works by Michelangelo and Van Gogh, as well as an unpublished Shakespeare play.

Continuity

 * Peri has the same hairstyle and similar clothing to what she wears in DW: The Mysterious Planet, placing this story closer to the events of that story than DW: Revelation of the Daleks.
 * The TARDIS' state of temporal grace, which renders weapons useless, does not function when the ship is in "normal space". (This is a possible attempt to rectify continuity issues created by several occasions in which weapons are shown being fired within the TARDIS.)
 * The Doctor returns to the secondary control room last seen in DW: The Robots of Death. The room includes a tea dispenser.
 * The Doctor mentions the Mandragora Helix, which first appeared in DW: The Masque of Mandragora.