Hogan is sharing a picnic with an Underground contact, Rhona, who also runs an art gallery. He wants three supply convoys destroyed before they reach their depot and is waiting on the route maps from his contact. Once he receives them, he will pass them to Rhona. Rhona suspects the Gestapo is watching her, so she gives Hogan her messenger pigeon, Alberta, for him to send word to her.
Meanwhile, Klink tells Hogan that he wants the prisoners to volunteer for some activity; this is so Klink can keep up with the other stalags. Hogan also notices Klink doodling, and pretends he can psychoanalyze Klink's personality from his doodles. Klink is impressed and wants Hogan to psychoanalyze more of his doodles.
The maps arrive, but they look like they have been through a shredder. Hogan and Co have to reassemble them, saying to Klink that they have taken up jigsaws as their activity. They reassemble the maps (with unknowing help from Klink), and send Alberta to Rhona with a message about a rendezvous at her art gallery. However a bomb, accidentally dropped from a German plane, causes the tunnel to cave in. Hogan has to find another way to get the maps to the art gallery. But of course inspiration soon strikes.
Hogan uses Klink's latest doodle to convince him that he has a talent for art (something Klink's teacher said he did not have) and take up painting. The results bear out the opinion of Klink's teacher, but Hogan is lavish with praise; his plan is to smuggle the maps to Rhona's gallery on the backs of Klink's paintings. For this purpose he persuades Klink to try selling his paintings there. Klink is so proud of his work that Rhona's unlucky contacts are forced to pay exuberant prices for them in order to get the maps. Rhona later informs Hogan that the convoys will soon be destroyed.
Believing he is on a roll, Klink buys back the paintings at even higher prices so he can sign them, and he promises Rhona more paintings. Rhona tells Klink that his work is as valuable as Van Gogh or Gaughin. Klink is overjoyed - until Hogan points out that those artists starved and it was not until after their deaths that their works were appreciated.