S1·E15 The Faustus Affair

Professor Quantum has created a seemingly useless machine that extracts the color out of everything in it's wake. A stranger, however, offers the Professor anything he wants in exchange for the Light Variator. April, posing as a lab assistant, has been sent to keep an eye on Quantum and he has fallen in love with her. The professor decides that what he really wants is his ""lab assistant"" and he's willing to turn over the machine if his wish is granted.