Gadget's Clean Sweep" is the 18th episode of the second season of Inspector Gadget.
Dr. Claw sends his latest M.A.D. agent, the frumpy Thelma Bodkin, back in time to the 1800s to steal the Crown Jewels of England. While there, she is also to knock off Inspector Gadget's ancestors ― a loveable pair of chimney sweeps named Chimney and Char Gadget ― the logic being that if they're killed, Gadget will never have been born.
Metro City Police get the word of the imminent theft of the jewels and Quimby orders his top man back to the past (through a time machine) to prevent it. Gadget, Penny, and Brain soon arrive safely along a waterfront in 19th century England, but the easily-distracted inspector immediately forgets his assignment after bumping into his great grandparents and instead visits with them. Bodkin, having already arrived, enlists the aid of a pair of two-bit hoods (very reminiscent of Cruella de Vil's henchmen in One Hundred and One Dalmatians) to finish off Gadget and his relatives while she heads off to steal the jewels. At the palace, Penny is recognized by Bodkin and locked in the dungeon, but managing to break free, she runs out and buys a cheap imitation of the jeweled crown to leave in the real one's place.
Meanwhile, on the rooftops of London, Char, Chimney, and Gadget are attacked by Bodkin's thugs. Eventually, Gadget's clumsiness (with Brain's help) thwart their efforts, and none too soon either ― Gadget, Penny, and Brain have to rush back to the time machine before it automatically returns to the present, with or without them. They board the machine with nanoseconds to spare. Bodkin arrives back safely, too, with crown jewels that Claw instantly recognizes as phonies.