When Maol Chalvim died in 954, he asked his older two sons, Duff and Kenneth II, to look after her; they gave him their word that they would. The ambitious lord Indulf took advantage of this to capture Katharine and use her as a hostage to prevent Duff and Kenneth from challenging his usurpation of the Scottish throne. Katharine was held a prisoner at Indulf's court for the next eight years, alongside her son Malcolm.
In 962, however, Robbie helped Prince Malcolm escape from Indulf, and Katharine subsequently threatened to throw herself off the castle battlements, thus costing Indulf his only hostage, if he did not yield to her stepsons. Indulf was forced to thereby abdicate and go into exile in Ireland, while Duff became King of Scotland. When Duff was slain at the Battle of Gaine in 967, however, Katharine had to go into exile with Kenneth and Malcolm; on the way to England, she caught a fever and died of it. Presumably Princess Katharine was named after her.