Irresponsible charmer Arthur Bach (Russell Brand) has always relied on two things to get by: his limitless fortune and the good sense of lifelong nanny Hobson (Helen Mirren) to keep him out of trouble. Now he faces his biggest challenge--choosing between an arranged marriage that will ensure his lavish lifestyle or an uncertain future with the one thing money can't buy, Naomi (Greta Gerwig), the only woman he has ever loved. With Naomi's inspiration and some unconventional help from Hobson, Arthur will take the most expensive risk of his life and finally learn what it means to become a man, in this re-imagining of the classic romantic comedy "Arthur."