After her husband was deposed in 1399, she was imprisoned in Sonning Palace. While there in 1400, she met the First Doctor, Ian Chesterton, Barbara Wright and Vicki Pallister. She and Vicki travelled to London in the hope of freeing her husband from captivity.
She was greatly upset when she learned of Richard II's death. Having been denied food on the orders of the Archbishop of Canterbury Thomas Arundel, he starved to death in Pomfret Castle, where he had been imprisoned. Henry IV hoped that she would marry his 13-year-old son Prince Hal but she had no intention of doing so, describing him as a "spotty boy".
Behind the scenes
Isabella's father is Charles VI of France, however this connection is not known to have been made in any Doctor Who fiction.