Mathematician Dr Hannah Fry uses Dr Xand Van Tulleken as her guinea pig to test whether the algorithms that dating sites use to match people actually work. While Hannah builds a dating site, Xand meets the scientists investigating online dating - and learns what pictures to use and what to write in his profile. He tries out a 'bot' that has automated a swiping app and has an MRI scan to find out whether his brain is equipped for love. 50 members of the public take part in some mini experiments at a date night - and Xand goes on various dates to test whether the algorithm is better than him choosing randomly.