Underwood and Fenton had in their possession the goblet found by Maurice Bernard, having killed Bernard to obtain it. They saw it as a weapon of great power to be used in a potential war.
When they caught the Seventh Doctor and Ace in their headquarters, they captured Ace while the Doctor escaped. They offered the Doctor a trade: the goblet, which the Doctor had taken, for Ace.
When the exchange took place, Underwood and Fenton managed to escape from the Doctor and his ally, Gerold Rösler. As they ran, Rösler shot at them. The shot hit the goblet, causing it to release a surge of energy and incinerate Underwood and Fenton. (PROSE: Ante Bellum)