Portal 2 follows the player-character Chell's fate after the end of Portal. Retroactively patched just prior to the sequel's official announcement, the ending of the first game shows Chell being dragged away from the remains of GLaDOS by an unseen figure with a robotic voice, later identified by writer Erik Wolpaw as the "Party Escort Bot". She is placed in stasis within Aperture Science for a period of many years, during which the facility becomes overrun by decay and nature. The Aperture setting is part of the Half-Life series; while Portal's events occurred before Half-Life 2, the sequel takes place much later than that game. One hidden area of the game shows the former location of Aperture Science's cargo ship, the Borealis, in the bowels of the facility; this ship is mentioned as part of the Half-Life universe at the end of Episode 2, having been discovered in the Arctic, situated in a seemingly-impossible position with all hands lost. Portal 2 suggests the ship was related as a result of an experimental teleportation device being developed by Aperture to compete with Black Mesa Research Facility, a competitor featured in Half-Life.