Crippling housing prices, accumulated student debt and loans are just the tip of the iceberg for millennials. Buying a home is seen as the ultimate unattainable vision for anyone born in the past 35 years. So for Matt Hartley's play Deposit, Generation Y is put firmly in the spotlight. As far as social observation pieces go, Hartley's play is the mini kitchen sink drama that 21st century society needs.

Hampstead Theatre's Downstairs space constructs the perfect intimate atmosphere for a play that takes place solely within the suffocating four walls of a one-bedroom flat. The staging heightens the claustrophobia and we are invited to peer voyeuristically into the characters' most private thoughts and feelings.

The story focuses on two couples as they undertake their most challenging chapter to date. The deal? Live together in a small London flat for a year. In that time they must sacrifice luxury (because a coffee everyday adds up) and save for the ultimate end game – a home of their own. But with four strikingly different personalities existing under one roof the renters must sacrifice more than just coffee.

Rachel (Natalie Dew), a primary school teacher has been in love with her boyfriend Ben (Ben Addis) for almost half her life. Ben meanwhile, an 'average' bloke, is just about to hit his 35th birthday with no ambition or life plan. If they save up enough money for a year they can just about scrape together enough for a deposit. Enter best friend of 15 years, Melanie (Nicola Kavanagh) and her boyfriend Doctor Sam (Karl Davies), a stickler for the finer details and avid chess player. The foursome create a contract based firmly on the trust of their friendship. But with what is little more than a pinky promise, what could possibly go wrong?

While the flat is no palace, it does boasts views of the Shard – well, that is if you look 'just a little to the right, there you can just about see the top of it'. For the foursome the leaking, mold-infested dwelling becomes home. Time passes, eloquently exaggerated through director Lisa Spirling's slick choreography. And as furniture moves around the stage, key moments of their year are played out. The foursome go from partying all night to increasingly getting under each other's skin.

The ever-growing irritability taps into financial insecurities and anxiety over careers. While arguments over milk and toothpaste may not seem like the be all and end all, they are the very things that make this play so down-to-earth. The cast likewise achieve this unflinching reality by showing just how easy it is for relationships to disintegrate – be it over milk or more seriously toxic jealousy.

Deposit doesn't necessarily offer the great resolution we hope for – but isn't that just like real life?