"Chicago, May 1920" is the name of the second half of the double-length episode Young Indiana Jones and the Mystery of the Blues. While Mystery of the Blues was broadcast as a single episode in the United States and several other countries, it was separated into two one-hour episodes for broadcast in the United Kingdom: "Chicago, April 1920" and "Chicago, May 1920".
The bookend clips for "Chicago, May 1920" included scenes of Old Indy (played by George Hall) with his grandson, Spike, an aspiring rock musician. The neighbors are complaining about noise from Spike's band practicing in the garage, when Indy recounts his tale - and keeps the fuse to keep the band from being amplified.
For information on the plot, cast and characters of the main part of the episode, refer to Young Indiana Jones and the Mystery of the Blues: Chicago, May 1920