Homer doesn't begin the Trojan War with Leda's twin eggs: he always rushes toward the outcome, and he carries the listener along with him into the middle of things, just as if they were familiar.
You hit the ground running
Most epic poets plunge in medias res
(Horace makes this the heroic turnpike road),
And then your hero tells when'er you please
What went before by way of episode,
While seated after dinner at his ease,
Beside his mistress in some soft abode,
Palace, or garden, paradise, or cavern,
Which serves the happy couple for a tavern.
“I’ll tell you my story in a way you can understand, with a beginning, a middle and an end. We’ll start in the middle.”
—Professor Paradox, Ben 10: Alien Force
Start as late in the story as possible.
That wasn't the first time I met the Doctor, and it certainly wasn't the last. Oh no. I just put that at the beginning because it's a brilliant opening.
—Elton, Doctor Who, "Love and Monsters"
Bravoman: How did we get up here anyway? I don't even remember him capturing us.
Alpha Man: I'd wager the show's writers wanted to start us off "mid adventure" it's a writing technique called in medias res.
Bravoman: In mid whawha?
Alpha Man: I believe it's latin for "skip the boring parts".
—Bravo Man Episode 1
Proper story's supposed to start at the beginning. Ain't so simple with this one.