Melinda helps one of Eli's new patients, the uber wealthy, obsessive compulsive, cute 40-something internet maven NATHAN WEISS. He locks himself in a safe room in his mansion every night because he feels he's being watched and someone's out to get him. This is only exacerbated by the security cameras that show him areas where security has been breached but no one shows up on the camera. Nathan thinks he's being haunted by his sister's ghost. who was kidnapped & killed when they were younger. Melinda discovers he's actually being haunted by the ghost of an old girlfriend, Amy, he had before he was famous. The relationship ended abruptly and Nathan would never talk about it. He became a recluse, diving into his work. Melinda and Delia look Amy up and discover she died recently from breast cancer, very much in debt and was survived by her husband and 21-year-old son, Garrett, a brilliant MIT grad. Melinda suspects that the son is really Nathan's but when they ask him about it, he has no idea what they're talking about. Amy finally shows herself to Melinda and explains that Garrett only found out about his real father after she died and feels that Nathan abandoned him and his mother. They figure out that Garrett got himself hired by Nathan's company to do something to get back at his father. Melinda and Nathan try to find Garrett while Garrett himself is working on releasing Nathan's secret security software to the public free of charge. In doing this, he unwittingly locks Melinda and Nathan in the panic room and releases a poisonous gas. When Garrett discovers this, he saves both Melinda and Nathan and Amy brings both her son and his father together, telling them how she tried to keep them from each other. Melinda crosses Amy over having reconciled everyone. Melinda and Jim are concerned even more when Aiden talks about his shiny friends that aren't ghosts but something else.