Fulfilling our mission would undoubtedly be the most important thing to happen on Earth that day, but Seiji seemed more interested in window-shopping.

I tried to hurry him up by indicating the faint but present glow of my ring, but he continued babbling about the elegance and charm of the Shibuya train station and its stalls of books and bento boxes and knockoff handbags. I lifted my hand again. He promptly darted into a tiny shop selling luxury sweets. Perhaps his human body was experiencing hunger. Mine was experiencing heat. The air smelled and felt like sweat. I wrapped my arms tighter around my body and edged into the chill radiating from the sweet shop's glassed-in case.

Seiji pointed to a square of clear gelatin with a gelatin goldfish plus a tiny frog on a lily pad suspended in its center. "What's that one called?"

"Wakabakage," answered the saleswoman. "Young leaves' shade. Very popular in summer."

"I'll take two," said Seiji.

"I don't want any," I said. "I hate things that wobble."

"And two without gelatin for my grumpy friend," he added. "What do you recommend?"

The saleswoman politely held her hand over her mouth as she laughed. "Do you like red bean paste, ma'am?" she asked me. "Or do you prefer white? Do you enjoy sticky rice? Or perhaps plain molded sugar? We have some very pretty hard candies. Or—"

I turned to Seiji. "If I pick two, will you come do your job?"

"If you eat them afterward," he said swiftly.

"Deal."

The saleswoman, amused, said, "Pinky promise? Or hand-shake?"

Seiji exhaled slowly. I let him squirm. Finally, he said, "It's too hot for that. I'll trust her word."

I had meant to choose randomly to underline exactly how much I did not care about edible things, but I lost my resolve when I looked into the case. There's no place like Japan when it comes to transforming sugar, gelatin, bean paste, and plant extracts into works of seasonal art. Fan-shaped rice crackers were printed with fireflies, waterfalls, and shooting stars. Morning glories and bellflowers of rice-flour dough bloomed at the banks of a rippling stream made of little curls of blue sugar.

"That, and that." I pointed to a wedge of cake with beans on top and a ball of white and blue strings.

"Yuzusumi, evening cool," said the saleswoman as she briskly packed my selections. "The bean paste strands represent people sitting on their porches to enjoy the night air."

I raised my eyebrows at her and Seiji to indicate my belief that the squiggly bits of bean paste did not resemble people sitting on their porches. But he only smiled cheerfully at me—I admit, his facial expressions were much more practiced than mine—and the saleswoman did not seem to notice.

She continued, "This is minazuki, the month of water. The rice flour cake is white to remind you of ice and make you feel cool. The azuki beans on top are to scare away evil forces. It was originally for a ritual performed in June that's supposed to make you live for a thousand years. Maybe just eating it will get you five hundred!"

"Maybe we'll each live for two hundred and fifty if we split it," said Seiji, before I could reply.

He paid, sliding his money into the tray provided for that purpose. The saleswoman returned his change to him the same way. No need to awkwardly drop money from a small height to avoid touching hand to hand. It occurred to me that I might have discovered the real reason why he liked Japan.

The saleswoman snatched up an extra sweet, wrapped it in green tissue paper, and popped it directly into his hand. "Special gift for you. Enjoy!"

I suddenly had the horrifying thought that the human might be flirting with him. And the even more horrifying thought that he might attempt to flirt back.

"Seiji!" I grabbed his shirt-sleeve between my fingers and yanked. He reluctantly skulked away from the shop, clutching his sugary prizes.

It was hard to avoid touching the commuters as we paced around the station. If the weather and local customs had permitted it, I would have covered myself from head to toe and worn my ring on a chain around my neck. For our last mission, when we had been college girls named Sigrid and Rikke, we'd fumbled for our rings with mittened hands. But today I was Riko, a stylish lady in a Tokyo summer, and my face and throat and hands were bare and exposed.

One of the many dark-suited businessmen was the first human to brush against me. As his fingers bumped against the back of my hand, skin to skin, I saw him in a homeless camp in Ueno Park, huddled inside a wooden box covered in blue plastic. He was naked and wrapped in a blanket. His suit was folded neatly atop a newspaper. It was the only clothing he owned.

"Steady," said Seiji.

"I'm fine."

The light from the precious chips set into our rings shone slightly brighter than it had at the sweet shop. We made a circuit of the entrances to the various lines. Commuters dashed for their trains and jostled against us. I was touched by a teenage boy who was being bullied in school, a fashion designer who despised her customers, and a grandmother mourning the twin sister who had died when they were sixteen.

"Interesting. . . ." Seiji looked thoughtfully at a young businessman whose only distinguishing feature was a streak of stubble that had evaded his razor that morning. "I wonder. . . ."

"We're not here to save them," I reminded him. "And look at your ring. The shard is down there, at the Chuo line."

We followed the increasing light in our rings down to the escalator until we had to pocket them or risk attracting attention. The fragment was clearly somewhere on the platform. I began to search. Seiji wandered over to inspect the vending machines.

"It didn't fall into a can of coffee," I said. "Get to work."

Seiji fed some coins into the machine and got his coffee. Water drops condensed on the can's icy surface, merged together, and dripped down. His face too glistened with sweat when he looked at me. "Riko . . . do you ever think that maybe the breaking of Heaven was part of the great plan?"

"Of course it was. Nothing is outside of the plan."

"But why?"

"To wake us from complacency," I recited dully. "It took a great catastrophe to force us to acknowledge that the war continues."

"Maybe it was because we were so happy in Heaven, we forgot to love Earth," countered Seiji. "Maybe it was to remind us that underground in Tokyo, women are selling sweets called little chestnut, and water's edge, and summer frost."

"That's the most self-centered thing I've ever heard!" I shouted. Despite the roar of a train pulling out, people turned to look at me. I lowered my voice. "You think Heaven was destroyed, and we were all scattered with no guidance or purpose except what we made for ourselves—for no better reason than to teach you the joys of sweet bean paste?"

Seiji pursed his lips stubbornly. "Well . . . yes. And to teach you too. Has it been so long since you've felt any joy that you've forgotten how important it is? We were made to rejoice as much as we were to fight, or search, or anything."

"Lay your skin on the shard when you find it," I said coldly. "And then talk to me about joy."

I walked to the other side of the platform and peered down at the tracks. A woman leaped off the platform into the path of the oncoming train. I turned my head so quickly that pain seared through the muscles in my neck. The train had not yet arrived, and the woman stood beside me at the edge of the platform, her face blank and her bare hands very near mine.

"I found it!" Seiji dashed up beside me. He had a handkerchief wrapped protectively around his hand—so much for joy—and nested in the cloth was a small opalescent shard. My ring was hot. His must be burning his finger.

The platform began to vibrate. A hum filled the air. The train was coming. I grabbed the woman beside me, skin on skin. With my other hand, I dragged Seiji's upward, brushing her cheek with the shard of Heaven.

A little girl ran through a field. The weeds came almost to her waist, and mud squelched between her bare toes. She cupped a tiny green frog in her hands. "Mama!" she called. "Mama, look!"

The woman staggered back from the platform's edge, jerking her hand out of my grasp. It had been pure impulse to try to stop her, let alone to use the shard. I had never seen a human touch one before. I had expected her to see Heaven whole, not a child with an amphibian. But that was what it had showed her, so it must be something a human would consider important.

"You're not going to let your daughter grow up without a mother, are you?" I asked her.

A shockwave of hot air buffeted us as the train pulled up. The doors slid open. Passengers spilled out and in.

"I don't have a daughter," replied the woman. With a fragment of actual Heaven in her view, she was inexplicably ignoring it in order to stare at Seiji and me.

"I was that little girl," she said. "It seems so long ago. How could I have thought of harming that beautiful child?"

She turned her back to us and stepped aboard the train.

"Wait!" I shouted. She glanced back at me expectantly, but I didn't know what to say to make sure the moment stayed with her. Seiji understood humans better than I did, but he was silent. I snatched the paper bag of summer sweets that dangled from his other hand, and thrust it into hers.

She took it. The doors slid shut. The train pulled out. A moment later, she was miles away.

Seiji pocketed the shard. I was right: his mortal flesh was burned red around his ring. "'We're not here to save them?"' he quoted back at me.

I ducked my head as if his words were shrapnel that might pierce my skin. "We made the retrieval."

"I don't mind," he said blandly. He picked up his coffee can from a bench and popped the tab. "I'm just surprised."

Seiji was as annoying as . . . the place of the enemy . . . but he was also the only person who could possibly understand. "I couldn't let her abandon whatever task she might have."

"Are you afraid you might abandon yours?"

"No!" I snapped. "Never! I'm afraid you might!"

He shook his head. "I'm enjoying myself far too much."

"How can you? We had perfection . . . a home . . . a purpose . . . and now it's all gone. We're trying to rebuild what was infinite out of a few tiny broken pieces. It's impossible!"

"They say ten thousand angels can dance on the head of a pin." Seiji closed his naked fist around the shard in his pocket, and his face changed. He extended his other hand. "Dance with me."

He caught my hand before I could step away. We danced and swam in a river of light, and the living stars, as numerous and individual as the passengers on the Chuo line at rush hour, shone and sang in glorious chorus. A moment, an eternity; and then I stood on a grubby concrete subway platform in a Tokyo summer of 98 percent humidity and 98 degrees Fahrenheit, a woman with aching feet holding hands with a pudgy, middle-aged businessman.

Seiji put the shard back in his pocket.

"You're an egocentric, lazy, gluttonous idiot," I said. "But thanks."

"Any time."

Seiji pulled the crumpled little paper bag from his other pocket and took out the "special gift" sweet. It was a slightly squashed rectangle of pale green gelatin with a curving line of white flecks swirled through the middle.

"Ama no gawa," he said. "The River of Heaven. It commemorates an old story about two stars in love. Once a year they cross the Milky Way to meet each other."

"I bet it looks better than it tastes."

"Let's find out."

The next train pulled up. The commuters rushed past us, brushing against my skin: a crush of businessmen, college students, artists, schoolboys, tourists, babies in carriages, old-fashioned ladies in polyester kimono, immigrants, craftswomen, criminals, saints, and a fluffy Pomeranian in a sailor suit. Maybe we weren't the only angels. If I touched them all, I could find out.

I wondered if perhaps it wasn't Heaven that we were meant to repair. And I held out my arms and spread my bare fingers wide as we headed up the stairs toward the exit, where traffic signals and summer branches were silhouetted alike against the blazing light.

This story is dedicated to Yoon Ha Lee.

Wagashi descriptions were adapted from and the story was inspired by Wagashi, by Kazuya Takaoka, Mutsuo Takahashi, and Hiroshi Yoda.