That's the hour all businesses and individuals are urged to turn off the lights, and generally reduce power, to heighten awareness of energy use.
It's a symbolic global event, initiated by the World Wildlife Federation. At least 49 communities across Canada are participating.
The hour falls on a Saturday at 8 p.m., the time movie theatres are at their busiest.
Somehow Cineplex theatres have to co-ordinate the shut-off so that patrons in the lobby aren't stumbling over each other in the dark, cashiers are giving the right change, customers at the burger outlet are able to find the serviettes and passersby aren't assuming the theatre is closed.
"This is something that is quite logistically challenging for us as an organization to do, given the physical layout of the buildings," said Cineplex vice-president Pat Marshall. "It's not a matter of going into an electrical room and switching lights on and off. It could take us 20 minutes to be turning off the lights around the facility, and 20 minutes to be putting them back on."
So complicated is the variety of light and power sources in each theatre, a dry run will be necessary to make sure the event goes smoothly.
At the Scotiabank Theatre at Richmond and John Sts., they will also shut the down escalator, but not the up. That's a four-storey climb not everyone is able to make. Using the same logic, the theatre will make sure the elevator is still working.
"No plan ever survives the battlefield," Marshall said.
"We think we can turn off this lighting, and this lighting, and this lighting and this power source, but we want to time it so we know it can all be done in a certain period of time and we also know how many people are needed to do it.
"We want to communicate to our guests why we're doing this because, unfortunately, there will be a number of people who won't be aware of the initiative," Marshall said. "There will have to be an educational element layered on top of it all."
The burden of that element will fall on the cashier, the young person who takes your ticket or pours soft drinks. In a way, it's like any in-store promotion. The staff has to explain it to customers. "We're preparing a lot of documents teaching employees how to answer all the questions that they are going to be getting," Marshall said.
This is a main point of the exercise, of course: educating employees as well as patrons. "As one of the country's largest employees of youth, we feel it particularly important that our staff was aware of why it is important to support this."