The Magician's Birthday was originally meant to be a full concept album, but Heep's busy touring schedule made it impossible to finish. Therefore, the concept had to be squeezed into this song, with the other songs being lyrically and musically different.
The song was mainly written by keyboardist Ken Hensley, and the lyrics were based on a fantasy novel of his. The novel was basically about a good and an evil wizard challenging each other to a duel after meeting during the former's birthday party. The long instrumental section, with the dueling guitars and drums and the dissonant keyboard playing, was supposed to depict the battle.