Yonkle,
A novelist can write 300 pages with thousands of words to get his idea across to the reader. A lyricist, on the other hand, can take that 300 page book, condense and convey that same idea in three minutes and just a few words.
Take your three parts, beginning, middle and ending and write three 4 line verses that says the same thing as your story. Try to work rhymes into your verses. You don't need to use the same exact words that are in your story unless you want to, but really the trick is to "convey" the idea to your listener.
If there is anything that should be avoided in lyics, it should be "cliche's". They are cliches because they are used very frequently in every day language and basically are boring to a listener. Just like the many ways to chord a C on the quitar, there are many ways to say the same thing using different words. Now cliches are not totally bad and if used in a unique way are very cool. But that's a rare happening today.
These tools are your best friends when it comes to writing. A rhyming dictionary, a thesaurus and if you have it available, a book of quotations to refer to. Even the finest writers today don't just "come up with stuff". They have to use tools too.
Anyway, give the verses a whirl and see there they take you. You may be surprised how things turn out!
Les