The Day of the Clown is the second serial of the second series of the British science fiction television series The Sarah Jane Adventures. It was first broadcast in two weekly parts on the CBBC channel on 6 and 13 October 2008. The Day of the Clown introduces main character Rani Chandra (Anjli Mohindra) and her parents, Haresh (Ace Bhatti) and Gita Chandra (Mina Anwar), and they would stay for the rest of the series.

Luke and Clyde meet Rani Chandra, a new pupil at school who has moved into Luke's street. Clyde and Rani are stalked by a clown who was spotted prior to the disappearance of Clyde's friend Dave Finn, one of several disappearances of children in the past two weeks. Sarah Jane and Clyde link the disappearances of the children to the Museum of the Circus, Clyde and two of the missing children having received tickets for it. Rani, who wants to become a journalist, begins her own investigation and makes the same connection to the Museum having found a ticket in a school book belonging to one of the missing children and having a ticket herself.

Sarah Jane and Clyde explore the Museum of the Circus and encounter Elijah Spellman. As Sarah Jane, Luke, Clyde and Rani attempt to escape the building, Spellman reveals himself to have been the legendary Pied Piper of Hamelin and now Odd Bob the Clown seeking to take children away and feed off the fear of children going missing. When Rani's phone goes off, electromagnetic rays interfere with Spellman's energy. Sarah Jane, Luke, Clyde, and Rani escape the museum, and Rani accepts Sarah Jane's invitation to fight aliens.

The next morning, Rani looks out of her bedroom window and sees Odd Bob's balloon in her garden. When she gets to the school she tells Luke and Clyde, then a load of balloons fall down from the sky, all the school children pick them up (apart from Luke, Clyde and Rani) and fall under the spell from Odd Bob, behaving much like the Pied Piper story. However, Mr Smith uses the cellular phone system to interfere with Odd Bob's control and the children are released. Odd Bob suddenly kidnaps Luke, takes him to a place between worlds. Clyde uses humour to dissipate Sarah Jane's fear. Odd Bob requires fear to exist, and without it, he is in a weakened state and forced to return to the meteorite he used to come to Earth. Subsequently, the recently disappeared children return. Sarah Jane puts the meteorite into a box from which nothing can escape.

This was the eighth of eleven Sarah Jane Adventures serials to be adapted as a novel. Written by Phil Ford, the book was first published in paperback on 6 November 2008.^[8]