Holly, a freelance journalist secretly working for the CIA, was sent to Zanzibar Land in the fall of 1999 to gather intel about the growing disturbances in the country. About a month later all hell broke loose when Zanzibar Land captured Dr. Kio Marv in order to get his OILIX formula, whilst also threatening other nations with nuclear weapons. At this time Solid Snake was called back into FOXHOUND to commence Operation Intrude F014: the rescue of Kio Marv and OILIX. Once inside Holly offered support to Snake, mainly in terms of navigation as she was more familiar with Zanzibar Land.
Her cover was eventually blown, however, and she was captured. Luckily Snake rescued her from the basement of the tower building and the two finally met face to face, with Snake remarking that he didn't think she'd be so pretty. Holly went back to providing support afterwards, even digging up info on Dr. Madnar that revealed he was willingly working with Zanzibar Land on a new Metal Gear. After Snake acquired OILIX and defeated Metal Gear and Zanzibar Land's leader Big Boss Holly met up with him disguising herself as an enemy solider (though quickly abandoning the garb, as it was too tight on her chest) and the two fled Zanzibar Land's last remaining forces en route to an extraction chopper. Though a relationship seemed to be blossoming between the two and they'd made plans for Christmas dinner, Snake quietly snuck away after the mission; possibly to the wilderness of Alaska.
Holly has yet to appear again in the series. Her involvement in the Zanzibar Land disturbance was mentioned in the "Previous Operations" feature in Metal Gear Solid, though her name was mistranslated as "Horry". The mistake was corrected for the GameCube release of The Twin Snakes.