Scully begins to suspect that her partner's strange behavior is more than it appears to be, while Mulder fights to return his life to normal before it's too late.
As Scully becomes increasingly suspicious of the "new" Mulder, the real Mulder works to find a way to switch things back to normal. Holding Mulder back from trying to switch things back is an investigation into his abnormal behavior by his colleagues. When Scully discovers the truth about the switch, Fletcher reluctantly helps her and Mulder to try and set things straight.—Muldernscully