It began with a rainy afternoon and a pinky swear. Ten-year-old Rohan was moving to London with his family. Little Pooja, with pigtails and tears in her eyes, made him promise: “We’ll write letters. Every single week. And you have to reply.”

Beside them, Vishal smiled and added, “And I’ll make sure she doesn’t forget you.”

“And you forgot me,” Pooja whispered. “Which hurt worse?”

Rohan, Pooja, and Vishal had been friends since they could spell their names. Their friendship was a book with many chapters, but if you looked at its emotional index, three entries dominated the page.