As Brexit draws closer—Britain’s split from the European Union is scheduled for March 2019—the issue remains contentious nearly two years after British people voted 51.9% to 48.1% in favor of leaving the EU. How contentious? Just look at the goal of The People’s Vote.

What does The People’s Vote want?

Its main aim is to make the government hold a vote on the final Brexit deal once it’s agreed to with the EU. Leaders of the campaign stress that this wouldn’t be “a second referendum,” or, in other words, a mere repeat of the June 2016 vote. Instead, it will be a chance for voters to make an informed decision about the reality of leaving the EU rather than the “fantasy” they voted for nearly two years ago. The group argues that the circumstances have changed enough from what was promised that this new vote is warranted.

But it’s being misunderstood…

Leaders of both the Conservative and Labour parties, which don’t normally agree on much, have ruled out the possibility of holding a “second referendum”. Although members of The People’s Vote are quick to point out that they’re asking for a different kind of vote, pro-Brexit leaders in the Conservative party, which controls the government, say the public doesn’t want to vote on Brexit again. Foreign Secretary Boris Johnson, who was a prominent pro-Brexit campaigner, told the BBC that the people’s vote had already taken place, and that Brits had voted with “a substantial majority” in favor of Brexit.

Why does Patrick Stewart care so much?

In an appearance on the BBC before the rally on Sunday, Stewart talked about his childhood as a “war baby” and how he experienced the world as “not good” before the U.K. joined the EU in 1973. He also emphasized that the reality of Brexit has proven to be “quite unlike” the promises—less spending, improved public services, easier bilateral trade—made by pro-Brexit groups during the referendum campaign. At the rally on Sunday, Stewart said, “our country’s future is at stake and we will not stand idly by.”

What’s even going on with Brexit?

The People’s Vote launched during a critical period in the Brexit process. At 11 p.m. U.K. time on Friday March 29, 2019 the U.K. will cease to be part of the EU per the terms of Article 50. That means there’s less than a year left for the two parties to come to an agreement or face a “cliff edge” scenario where ties between the U.K. and the EU are suddenly severed with no arrangement as to how to move forward outside WTO rules.

The latest iteration of the deal would see a “transition period” of 21 months, during which time the U.K. would retain the benefits of the single market and customs union. Brexit hardliners have been disappointed at the government’s acquiescence on the Irish border, immigration, and trade deals with third parties, which will only be able to come into effect as of January 2021.