Ovid told Proserpina's abduction twice, in two different poems written for two different purposes, and the gap between the tellings is itself informative. The Metamorphoses version, in book five, is narrated inside a contest of song, dense with landscape and transformation, and it ends with the compromise brokered between Ceres and Jupiter that divides Proserpina's year between the upper world and the realm of Dis. The Fasti version, in book four, is calendar poetry, written to explain why the Cerealia falls when it does and what a Roman celebrant was actually doing on that day, and it lingers on details the Metamorphoses passes over: Ceres's nine nights of torchlit search, her arrival at Eleusis, the hospitality of Celeus, and the specific observances the festival asks Romans to keep in memory of the goddess's grief.
The calendar meaning is the whole point of the second telling. The Cerealia, held in mid April, falls at exactly the season when Italian grain sown the previous autumn is visibly greening in the fields, so Proserpina's return from below reads, in Roman practice, as an explanation timed to the agricultural year rather than a story told for its own sake. Ovid has Roman women carry lit torches through the observance in memory of Ceres's own search by torchlight, and he has celebrants dress in white and set aside certain foods for its duration, a kind of ritual mourning that lifts only once the goddess's daughter is restored. The myth is not decoration laid over the festival; in Ovid's own account the festival's actions are literally reenactments of what Ceres is said to have done, so an ordinary Roman farmer's calendar carried Proserpina's story forward every spring, whether or not he ever set foot inside a temple of Ceres.