Age 21.
Uchiha Michiyo gets married in the spring. Her husband is the always-grinning, always-blushing Uchiha she's been dating for several years now. They're young to be married, but Konoha knows the importance of love in a time of war. The entire Uchiha clan shows up and even Shimura Danzou makes an appearance for his former student, though lately he's been too occupied with his organization to pay them much attention.
Sakumo grins widely as he watches his best friend fumble around with her wedding dress, and helps her into her sandals. She snorts and asks him when he's finally going to get hitched. Their other teammate, Natsume, rolls his one remaining eye and says "Sakumo is far too shy for that," before going off to meet his own girlfriend.
Sakumo blushes and for a moment he and Michiyo remember their first kiss. Sakumo smiles at her, squeezes her hands and wishes her good luck.
xXx
That next week, he's assigned a covert mission with a new partner. He suspects she is ANBU, though she never says- but there's always a twinkle in her heavy-lidded eyes and though she wears a cloth mask, he can tell that she always has a smile for him.
He always has a smile for her, too.
Her name is Hanano Kinue, and she's the most brilliant person Sakumo has ever met. Her mind is like quicksilver, making connections before anyone else has even begun to grasp the situation. Her parents are civilians and she doesn't have much chakra herself, but she's so fast and so insanely clever that it doesn't really matter.
They play shogi on the long evenings where their target is motionless and they have nothing better to do. She beats him soundly the first few times, but takes pity on him and starts handing out advice. By the end of the week, he manages a draw with her. She grins and says he's pretty clever himself, then proceeds to soundly beat him once again.
Two weeks later she almost gets herself killed because while she is fast and clever, she's fragile too. She takes out their target in the process, but Sakumo has to carry her back to Konoha on his back.
He watches her in her hospital bed as she consoles her weeping mother and tells her everything will be fine; she's brilliant at that too, her eyes kind and caring and a smile caressing her lips. It's the first time he sees her face. She's drawn and pale, her dark hair is plastered to her skin and her nose is slightly crooked, but to Sakumo she's the most beautiful woman he's ever seen.
He tells Karasu after. The man laughs, drinks saké and tells Sakumo he's a sentimental fool for believing in love.
xXx
Kinue becomes a permanent fixture in his life, after that. They start dating and it's awkward and clumsy, but for the first time in years Sakumo remembers Ran and knows she is right; love is a peculiar thing.
Kinue is quirky and eccentric, reads all the wrong novels and has an embarrassing fondness for soap opera. She likes his hair long so she can thread her fingers through, so he thinks perhaps he should start growing it out. When he suggests it she laughs and says he'd never remember to brush it.
Sakumo introduces her to his dogs and when he sees her face light up at the sight of them, he knows he's in love.
xXx
22 years ago:
Encounters with enemy ninja become more frequent. One day they run into a group of Konoha shinobi and there is a horrifying moment where Sayuri thinks they might recognize her Konoha shinobi and brand him a traitor.
But he is clever, so much cleverer than she'd given him credit for, and he has transformed himself into a non-descript Snow ninja before she's even realized the Konoha shinobi are near.
He is injured in the scuffle that follows, a nasty blow to the shoulder that would have left a lesser man writhing in pain. In her rage Sayuri calls upon a storm and devastates their enemy, intent to leave nothing whole.
His eyes are fearful when he witnesses her power, but the set of his mouth is determined. "They're just doing their job," He argues. "Please come away with me,"
She takes his hand and the storm slowly rages down.
Update 17/2/17:
Changed Kiyame's name to Kinue after learning 'Kiyame' is not actually a proper name.
Kinue (絹枝), probably meaning 'silk'.