Using the Lie Absorber at April Fools' Day

April 1st. Gian and Suneo are plotting what lie they will tell to fool Nobita this year. Meanwhile, Doraemon tells Nobita to have fun telling lies with everyone, so he pretends to give Doraemon a dorayaki as a present and gives him a jack-in-the-box from which a toy mouse pops out.

Doraemon gets angry at being tricked, and Nobita says, "There's no such thing as being lied to!" When Doraemon asks for a good gadget, he takes out his "liar magnet," which can suck up lies.

After making the liar magnet recognize that Doraemon is a liar, Nobita presses the suction button as instructed by Doraemon. Then, when Doraemon says the name of a lie, only that lie is sucked up and only his mouth moves. What's more, he was surprised that he couldn't pronounce the "lie" part after that!

According to Doraemon, once a lie is told by a Uso-jiki, it can never be repeated. In order to solicit the lies of Gian and Suneo, Nobita heads to the vacant lot with the Uso-jiki in hand, but...!?