'Art Therapy' is the name of the co-op DLC later added to Portal 2. He uses art as an an attempt to help his schizophrenia.
The comic ends with the injured Rattmann crawling into a cryo-unit and putting himself to sleep. Upon finding Chell, he is unable to release her from her solitary confinement and, noticing that power systems are beginning to fail, he patches her chamber into a reserve grid, saving her life while at the same time trapping her for an unknown period of time. After Chell is abducted by the Party Escort Bot, he delves back into the crumbling complex in an attempt to rescue her. Following several flashbacks of Rattmann's employment at Aperture Science, he witnesses firsthand the ending events of Portal. Sneaking through the facility, he watches from the shadows as Chell is tested by GLaDOS.
The comic follows Doug Rattmann, a lab worker at Aperture Science with a history of schizophrenia, who survives GLaDOS's attempt to murder every employee in the Aperture Science facility when she is first turned on.