Imagine a storm, rolling west across Rohan. Imagine Boromir, son of Denethor, his horse spooked by a crash of lightning, staggering white-faced into Edoras with a broken arm. Imagine him, feverish, babbling about taking a message to the elves, about the Sword that was Broken and Isildur's Bane. Imagine Eowyn, niece of the king, taking up the challenge, taking her horse, and riding north towards the only Elven Wood she knows of. Imagine Galadriel, listening to her story, taking her under her wing.
Imagine the storm turning north, crackling over Mirkwood, driving the spiders of the south into King Thranduil's lands. Imagine Legolas setting out on his errand to Rivendell - but because of the added danger, imagine him taking a companion, one Tauriel of the royal guard.
Imagine the storm, fuelled by malice, passing over the Misty Mountains and flooding the passes. Imagine a party of dwarves, stopping over in Rivendell on their return from the Blue Mountains to Erebor, delayed by the weather. Imagine Dis, sister of Thorin, old but sprightly matriarch of Durin's line, living in the House of Elrond.
Imagine it breaking over the Shire on September 23nd, the day Frodo Baggins and Samwise Gamgee leave Bag-End for the last time. Imagine the weather's fury driving them to seek shelter in the Green Dragon Inn, where Sam whispers to his sweetheart Rosie of a journey to Bree - and beyond. Imagine Rosie's plan to go after him, to watch over him. (Imagine Merry and Pippin, running through a farmer's field, with no cousin to get in their way.)
Imagine Rosie's friends: Angelica Baggins, who sees a chance to find her Uncle Bilbo, and Pearl Took, outcast older sister of Pippin, who in her wanderings has journeyed to Bree many a time. Imagine them setting out together, not following Frodo, but seeking to reach the Prancing Pony first.
Imagine a reunion of five hobbits in an inn populated by Big Folk. Imagine Aragorn, struggling to deal with a rambunctious group of halflings. Imagine Pearl, slipping outside during the night. Imagine a screech from your darkest nightmares.
Imagine the Black Breath, come upon Pearl far from Elvish help, in lands where Athelas does not bloom. Imagine Aragorn leading the hobbits back west, over the Barrow Downs, to a lonely cottage in the eaves of the Old Forest.
Imagine Goldberry, mistress of the house, tending to Pearl's affliction. Imagine Aragorn, Frodo, desperate to move on - and imagine Pearl, unwilling to stay, despite her enduring weakness. Imagine Goldberry, cutting the Gordian knot: 'if she will not stay back, then the River-Daughter will go forth'.
Imagine seven figures traipsing through marshes, across lonely fields, to the forbidding crags of Weathertop. Imagine an ambush, a battle, Frodo grievously wounded. Imagine a flight, just a little slower, just a little further off the beaten track.
Imagine Arwen, taking Frodo before her, flying to the Fords of Bruinen. Imagine her defiance, and white horses crashing down on the Nazgul. Imagine Frodo, groaning in agony, tumbling to the ground.
Imagine they were just too late.
Imagine a Council where Bilbo is the only Ringbearer present, where Eowyn represents the Men of the South, where Legolas and Tauriel sit side by side, and Galadriel, Gandalf, and Elrond debate the fate of the world together. Imagine Bilbo volunteering - 'Bilbo the silly hobbit started all this, and Bilbo must finish it' - and imagine his devoted niece Angelica stepping into his place.
Imagine Rosie and Pearl, unwilling to leave their friend's side. Imagine Goldberry, a guide with water's skill at finding the least likely of paths. Imagine Eowyn, returning south with the party, and Galadriel stepping in to accompany them. Imagine Arwen, Elven Ranger, facing down Aragorn and insisting on taking the duty. Imagine Tauriel's eagerness to join - and Dis, stepping up over the objections of her entourage, following the woman her son fell in love with.
Imagine the Fellowship of the Ring - a different fellowship, a different path, different friends and foes along the way, and all because of a single storm, unleashed from the mind of Sauron with little thought for what it might accomplish.