The Oompa-Loompas Timeline and Summary

When we first hear of the Oompa-Loompas, we don't know they're the Oompa-Loompas. Grandpa Joe tells us about mysterious workers at Willy Wonka's factory who never ever leave.
Later, we see the Oompa-Loompas in the flesh, which prompts Mr. Wonka to launch into the story of how they came to be his workers.
It turns out Mr. Wonka rescued the Oompa-Loompas from Loompaland, and brought them to the factory, where they help make and test his chocolates.
Each time one of the Golden Ticket winners runs into disaster, the Oompa-Loompas sing an awesome, rhyming song about the kid (and usually help cart him or her off to safety).