Returning from Europe to the U.S. by plane, the Ricardos and the Mertzes must be very careful in packing their bags, since any luggage over 66 pounds will cost a lot of customs money. It so happens, however, that Lucy (Lucille Ball) has purchased a 25-pound slab of rare Italian cheese as gift for her mother, and she's not about to leave the gift behind. This explains why Lucy ends up on Pan American Airlines flight number 155 holding a bundle in her arms which she claims is a sleeping baby named "Cheddar -- ah, Chester!" And thus, with this classic I Love Lucy episode, the series' fifth season comes to a close. ~ Hal Erickson, Rovi