between me, the sand, and the sea

Oh, Carolina knows
Why for years they've said
That I was guilty as sin
And sleep in a liar's bed
But the sleep comes fast
And I'll meet no ghosts
It's between me, the sand, and the sea
Carolina knows
- Carolina, by Taylor Swift

Sirius survived the attack on the Department of Mysteries at the end of Harry's fifth year at Hogwarts.

Unfortunately, this doesn't prevent Harry from being forcibly returned to the dreaded Dursleys for the summer. And - lucky for him - they're going away to the beach for the holiday. With Mrs Figg busy tending to an ailing niece, they've got no choice but to bring Harry with them.

So, Harry's stuck as their relegated luggage-carrier while the Dursleys lounge in the sun and Dudley eats his way through all the ice-cream in Devon.

But one afternoon, when Harry sneaks away from his relatives for a moment to himself, he stumbles across someone in trouble. And, helping them? That might just change everything.

A Post-OOTP Canon-Divergence AU - with twists, turns, salt, sea, buried truths and a kind of magic that doesn't involve a wand...

TL;DR:
Sirius survived the Department of Mysteries, but Harry still finds himself exiled with the Dursleys for the summer - this time to the windswept coast of Devon. When he slips away for a moment of peace, he discovers someone in trouble. Helping them sets off a chain of events that unearth long-buried truths and a kind of magic Harry never knew existed.