<P> Florence is taken by Jonathan's mutated snake named Snakespeare, leaving Lewis and Jonathan to face the Izzards on their own . Isaac and Selena await as the lunar eclipse is setting, which will activate the clock's power . Lewis and Jonathan try to fight back, but Jonathan is transformed into a baby that still has his adult head . The eclipse begins, and people around town start to de-age to children . Lewis consults the Magic 8 - Ball to know what to do and it says "Say goodbye ." Lewis realizes he has to let go of his pain from losing his parents to harness his true power . He drops the ball into the clock's gears to slow it down, and using his own magic, Lewis blasts Isaac and Selena, causing them to fall, de-age, and ultimately be erased from existence . Everything goes back to normal as Florence reveals that she has fixed Snakespeare and Lewis asks her to be part of his new family . </P> <P> Lewis returns to school with more confidence, and gets revenge on Tarby and his friends by magically bouncing a ball on their faces, and befriends Rose Rita Pottinger . Jonathan then picks him up from school where they go home with Florence as the three of them are now like a regular family, as reflected in the stained glass window . </P> <Ul> <Li> Jack Black as Jonathan Barnavelt, Lewis's uncle and a warlock . </Li> <Li> Cate Blanchett as Florence Zimmerman, Jonathan's neighbor and friend and a witch . </Li> <Li> Owen Vaccaro as Lewis Barnavelt, Jonathan's 10 - year old nephew . </Li> <Li> Kyle MacLachlan as Isaac Izard, an evil warlock </Li> <Li> Renée Elise Goldsberry as Selena Izard, Isaac's wife and a witch . </Li> <Li> Sunny Suljic as Tarby Corrigan, a classmate of Lewis . </Li> <Li> Vanessa Anne Williams as Rose Rita Pottinger, a classmate of Lewis . </Li> <Li> Colleen Camp as Mrs. Hanchett, Jonathan's nosey neighbor . </Li> <Li> Lorenza Izzo as Mrs. Barnavelt, Lewis' mother . </Li> <Li> Eli Roth as Comrade Ivan </Li> </Ul> <Li> Jack Black as Jonathan Barnavelt, Lewis's uncle and a warlock . </Li>

The house with a click in the walls cast