"Turn the lights off!"

Rona and Miranda had been sitting in the dark for almost half an hour, and with their eyes completely adjusted to the candle-light the sudden intrusion of electric light when their housemate arrived home and started turning lights on was a startling and alarming occurrence. From the sitting-room they could both see her approach as the lights between her and them gradually got switched on: first the light outside the front door, then the hall light, then, most blindingly, the light in the sitting-room.

"Turn the lights off!" they both called out again.

Their housemate looked at them with bemusement tinged with irritation. "Why are you sitting here with candles lit?" she asked. She smiled to herself. "Testing out the smoke detectors?"

"Turn the lights off!" Miranda said again, as if it was a mantra, and even as she said it she jumped up out of her seat and strode double-time to the light switch on the far wall. She clicked it off and the room again started flickering under the spell of the candles.

"It's Earth Hour" Rona explained. "We've gotta have the lights off until nine o'clock."

"Oh man, is that tonight?'

"Don't you pay attention?" Miranda asked.

"Only to stuff that's important to me."

Miranda rolled her eyes, though their housemate couldn't tell as her eyes hadn't yet adjusted to the lower light levels. "This is important" Miranda said. "Global warming? Hello! It's the most important thing in the world!"

"Like us turning the lights off is even going to make a difference!" their housemate scoffed.

"It's symbolic" Rona explained.

"What does it symbolise?'

"Our willingness to . . . I dunno, do something."

"For one hour a year?"

"It's a start."

Their housemate sighed. "Can I turn on the T.V.?"

"No!" Miranda protested. "It's Earth Hour."

"It's not a light."

"It uses electricity."

"So I'm not allowed to use any electricity?" their housemate asked. "Well that's just fucking great. How am I supposed heat up my dinner? I'm starving!"

"Chill out" Rona said. "You've only gotta wait another . . ." she turned the light on on her mobile 'phone. "twenty-nine minutes" she said.

"Isn't that using electricity?" their housemate pointed out, gesturing towards the 'phone.

"That's different. It's in a battery."

"But where did the battery get its power from, eh?" Their housemate shook her head in disbelief at the situation. "God, just wake me up when it's over" she muttered, and left the room. The lights in the hallway and outside the front door remained on.

"Turn the lights off!" Miranda shouted.