Izzy was first introduced in End Game, which ran in issues #244-#247 of DWM, written by Alan Barnes and drawn by Martin Geraghty, where she was a 17-year-old science fiction fan and amateur paranormal investigator who lived in the town of Stockbridge, England.

When the TARDIS was swallowed by a gigantic snake-like spacecraft called Ophidius, Izzy and the Doctor met Destrii, an amphibious alien with the characteristics of a humanoid fish.

Destrii was being pursued by the group of aliens that controlled Ophidius, and gained Izzy's confidence only to switch bodies with her to evade capture.

During her time in that body, Izzy helped fight murderous artistic aliens in 1940s Mexico and made several friends who slightly restored her confidence.

Just as she began to adjust to her new body, Izzy was kidnapped by operatives of Destrii's mother, the Matriax Scalamanthia of the planet Oblivion, who wanted her "daughter" to prepare for her wedding by fighting a duel to the death.

While trying to trace Izzy's whereabouts with the help of his former companion Fey, the Doctor discovered that Destrii was still alive due to the 'disintegration' beam having a secondary 'storage' function.

Izzy appears as a companion to the Eighth Doctor in the Big Finish Productions audio drama The Company of Friends, where she is portrayed by Jemima Rooper.