When her idyllic vacation takes an unthinkable turn, Ellen Martin (Meryl Streep) begins investigating a fake insurance policy, only to find herself down a rabbit hole of questionable dealings that can be linked to a Panama City law firm and its vested interest in helping the world's wealthiest citizens amass even larger fortunes. The charming — and very well-dressed — founding partners Jürgen Mossack (Gary Oldman) and Ramón Fonseca (Antonio Banderas) are experts in the seductive ways shell companies and offshore accounts help the rich and powerful prosper.

he likes of 'The Big Short', 'War Dogs' and 'The Wolf of Wall Street' have shown that, very often, the most effective way to get audiences to swallow uncomfortable truths is to drench it in humour and pepper it with name-recognition actors. After all, the impotent rage you feel knowing that the super-rich gained that status by deception and flagrant abuses of the law can only be tempered when you laugh at pathetic the laws were to eventually stop these people.

'The Laundromat' takes this understanding to a new level, spicing the whole dish with Gary Oldman in a funny accent, Antonio Banderas being his most Antonio Banderas-y, and Meryl Streep playing a fuddy-duddy grandmother-turned-investigative genius. We're presented the story of Mossack Fonseca and their elaborate dealings in hiding people's money in offshore accounts through various vignettes, little tales of personal greed and avarice, the blasé manner in which the wealthy flaunt the laws the rest of us adhere to, all of which are well-acted and well-scripted.

Steven Soderbergh's direction and Scott Z. Burns' script blends together well, matching the screwball comedy of 'The Informant!' with the sickeningly impersonal examination of 'Side Effects' and 'Contagion'. There's no point in 'The Laundromat' where you're not seething with anger at it all, but it's all done with such pitch-black humour that it's only thing keeping you from turning it off and firebombing your nearest oligarch's compound.

Gary Oldman is clearly enjoying his ridiculously camp German accent, while Banderas flounces through each scene with his charm gleaming off his gold watch, yet the engine of the movie is Meryl Streep's twitchy performance as Ellen Martin, a grandmother turned dogged avenger. Robert Patrick and David Schwimmer float through the story as two put-upon business owners who are subject to a scheme run by Jeffrey Wright, while Nonso Anzie, Matthias Schoenaerts and Rosalind Chao are some of the intriguing side stories that ran tangentially from the main flow.

Soderbergh's use of humour and cynicism serves him well, as there really is a sense that nobody - not even the US - is free from the kind of deviousness on show here. Indeed, Ireland is itself guilty of the kind of tax evasion that's shown in 'The Laundromat'. Yet, it's in the final moments of the movie that it loses any sense of momentum and, instead, winds itself up with a cloying, earnest that undermines everything that's come before.

Still, 'The Laundromat' has its moments and while it's by no means Soderbergh's finest, it's an intriguing and bleakly funny assessment of how the rules don't apply when you're despicably rich.