Dick Tracy was dropped down a caisson at a suspension bridge construction site by the criminal night club owner and blackmailer Jacques. Jacques then had a huge boulder dropped down the hole, intending to crush Tracy.
Luckily, Tracy discovered that he was not in a caisson at all, but rather a ventilation shaft for an underground tunnel that was being built at the same time. He was able to call for help, and some workmen freed him just before the boulder came crashing down through the roof of the tunnel. Jacques was arrested shortly thereafter.
- The Caisson Death-Trap was one of the more notorious examples of the "seat-of-his-pants" plotting that Chester Gould engaged in. According to later interviews, once he had devised the trap, Gould could not come up with a way to free Tracy. His initial plan was to invoke a deux ex machina solution where he, as the creator, would simply erase the boulder and deliver Tracy to safety. This resolution was rejected by Captain Joseph Patterson who insisted that Gould re-draw the ending.