Takes place during episode 52 and 53 of Shippuden, focusing on Sakura's thoughts and reaction to seeing Sasuke for the first time in years.
"Sakura," his voice rang out from above. She stopped dead in her tracks. He had always had a physical effect on her. When they were children, just his acknowledgement was enough produce so much dopamine, serotonin, and norepinephrine in her brain that she'd be love drunk for a full week. This wasn't that. She felt sick. She felt like she'd been sucker punched.
She dared to look up. He was bathed in shadow so she allowed herself to remember his eyes, black as pots of India ink, looking back at her as she pleaded with him not to leave. It was a mistake to think of it. She regretted it instantly, her stomach so twisted that her breaths became shorter.
And now he's close to Naruto, toying with the idea of killing him, but seeing them together is too familiar. She expected their bickering to begin, she expected to see a good-natured smirk dance at the corner of Sasuke's mouth that he tries to maintain his cool facade. She watched him lie, saying the only bond he ever felt was one of hate and it was for Itachi, saying that he doesn't need to explain himself to Naruto.
She ran at him, her chakra vibrating, fully expecting his Sharingan to anticipate her move. Fully expecting to look into India ink as she breathes her last breath. But Yamato meets him quicker than she could and takes the blow for her. It's a blow he can actually survive.
Naruto grimaces at Sasuke. Why do this? he asks. Orochimaru just wants your body. Sasuke answers that he'd do anything to kill Itachi. If the situation weren't so dire, Sakura might have laughed. It was oddly close to what Naruto had said just an hour earlier, about going to the ends of the earth to kill Orochimaru and get Sasuke back.
Sasuke falls back, performing the hand signs to kill them all at once. Sakura regrets not running faster earlier. She regrets not dying within inches of him.
Not loving him enough right then.
Not loving him enough when she was trying to convince him not to leave.
Not being able to take his pain away, shoulder it herself.
And before the last hand sign is performed, Sasuke is stopped by the most vile thing in the world, followed by the second most vile. And the most vile thing tells Sasuke not to kill her. They disappear with Sasuke in a burst of flame.
She hears Naruto sobbing. She wants to hold him, to sob too. But she promised Naruto that she'd get stronger, so she clenches her fists instead. She remembers back when she was stupid enough to fantasize about Sasuke coming home. In her mind, his apology would be inadequate for the pain he had put her through, but she'd throw her arms around him all the same. Tears welled up in her eyes as she told Naruto that they just needed to work harder next time. This isn't over.
She walks home slowly beside Naruto. Sai and Yamato stay a good several meters ahead. They do not exchange words, but the shared agony they feel is enough to bond them for life. She couldn't have picked a better teammate to go through this with. When the two finally walk through the gates of the village, her resolve is hardened. Next time she sees Sasuke, she will bring him back or she will die trying.