So I was going to post the conclusion to the Music Master's first case, but eh...after a while one MM story begins to seem pretty much like the next. Instead, I bring you this very cracky four-page PSA for war bonds, from Reg'lar Fellers Heroic Comics #15 (Nov. 1942). Scans for this public domain work are courtesy of ComicBookPlus.com.
Trigger warning for the usual sort of WWII-era racist caricaturing.
( 'Now we'll go to Europe...on wings of song!' )