Finally, dazed and grinning crazily, the crowd allows itself to be coaxed toward the exits. Some, like Milton, linger a little longer, struck dumb by the spectacle. Even after being temporarily overcome by that brief, exhausting bad trip, I’m aware that this hasn’t merely been a concert. It’s been an extravaganza. More grandiose, sonically sumptuous, and just plain strange than anything we’ve ever before witnessed. (Is it possible that somewhere during “How Many More Times,” Page segued briefly into the theme from The Woody Woodpecker Show?)

The rink is emptying, leaving behind disarray: folding chairs on their sides, flattened, turned backward; the floor awash with empty beer cans, crumpled cigarette packs, soda bottles. On the PA, someone exhorts us to quickly head to the exits.

Milton looks at his watch. “It’s after one.”

Realization strikes us both: Where’s Arno?

In the darkness outside the rink, police with megaphones are urging everyone to leave the park. Searching for our friend, Milton and I wade through the tide of spent, trudging post-concert bodies until Milton grabs my arm and points.

Thirty feet away, in the faint illumination of a lamppost, Arno is gesticulating to a police officer. For an instant, I’m gripped with fear that he’s been busted with the acid. But he’s not handcuffed. The red-and-white cap pokes out of his back pocket. The police officer’s arms are crossed, and there’s a scowl on his face.

The cop turns away. Arno’s face is contorted in iodine and baby oil sunburned outrage. He sees us approaching and complains, “Stupid cops won’t do anything.”

“About?” Milton asks.

“Clyde ripped me off.”

It takes a moment to piece together.

“You . . . told that pig?” Milton asks in astonishment.

“Damn straight. Think I’m gonna let some scumbag get away with my five hundred bucks?”

Another officer appears on the walk. “Move along now, boys. Out of the park.”

I’ve come down from the Windowpane enough to be geographically aware. Most of the crowd is leaving through the Grand Army Plaza exit at 60th Street. But Arno turns uptown, meaning we came in through an entrance farther up Fifth Ave. In that direction, the park path is shadowy and nearly deserted, the night air practically muted. All that remains of the concert is the ringing in my ears.

“So, I’m curious,” Milton says. “What did the pig say when you told him you’d given Clyde five hundred bucks for LSD?”

“Jerk laughed at me,” Arno growls bitterly. “I don’t get it. Isn’t it robbery? Theft under false pretenses or something?”

The hand that comes out of the dark feels disembodied when it clamps over my mouth. But another hand grabs my wrist and wrenches it behind my back with more than enough force to be convincing.

“Hey!” I let out a muffled yelp. A bolt of hot red pain shoots through my shoulder.