Mathew O'Hara was a business executive employed at the New York City offices of the Butler Institute. He was the husband of Anne Marie O'Hara and the father of Patrick O'Hara.

During the environmental crisis of the early 21st century, when pollution was so severe that the planet was reaching the point of no return, O'Hara conceived of a plan for humanity to survive by having copies of their minds uploaded into computers. In preparation for this, he had a project site constructed near his home in the Catskill Mountains to serve as a bunker to house the computers. He tested the procedure with James McIlveen and his own son.

The Seventh Doctor learned of O'Hara's plan and sought to defeat it with the help of Vincent Wheaton, a boy with psychic powers, and Justine, an environmental activist. The plan was for Vincent to use Justine's anger at the destruction of Earth's environment to destroy the site. This failed because Justine fell in love with Vincent. However, when O'Hara grabbed Vincent, the boy used his coldness to destroy the site and him. (PROSE: Cat's Cradle: Warhead)

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