Arthur (Russell Brand – Get Him To The Greek) is a billionaire who hasn’t grown up. He loves partying, drinking and spending copious amounts of cash on life’s frivolities. His mother Vivienne (Geraldine James – Calendar Girls) threatens to cut off his money supply unless he settles down and marries Susan (Jennifer Garner – Alias), an ambitious ex-girlfriend only concerned with increasing her social standing. So Arthur begrudgingly accepts this to preserve his way of life. But soon afterwards, he meets Naomi (Greta Gerwig – Greenberg), a local tour guide and wannabe children’s author. The two hit it off instantly but with Arthur now engaged, he has a tough choice ahead – get married to the wrong woman and be rich for life or give up all his wealth for potential true love. Perhaps his nanny Dobson (Helen Mirren – RED) can help guide him?