In an unexpectedly quirky and warm film, Michael Mosley sets out to find out what intelligence is, and where it comes from. A visit to an international Mensa meeting inspires him to want to join the elite club, and with just weeks before his Mensa test, Michael wants to try techniques to boost his brain. UK memory world champion Ben Pridmore agrees to mentor him, and he tries a groundbreaking neurofeedback technique that has helped eye surgeons improve their performance. In an attempt to understand where intelligence comes from, Michael meets America's most intelligent man, a former bouncer, and attends an institute claiming to teach babies to read. He participates in an alternative intelligence test, and competes in the world memory championships in Bahrain, but it is the IQ test that really counts; has what he has learned helped him to pass the Mensa test?