The Bureau of Weights and Measures is an amazing place where everything in the world is measured and assessed to make sure it is the right size, weight, temperature and so on. The engineer Marcel Gram does this important work. One day, Marcel's son returns home with something he can't measure-a mood. There's only one thing for it: they'll have to invent a new machine to measure the mood. Soon, father and son are inventing machines to measure every emotion! However, once they start letting other people use their inventions, things start to go wrong. Ingenious, funny and thought-provoking, and brought to life by Vincent Mahe's distinctive retro illustrations-Anne-Gaelle Balpe's story is both a celebration of science and a warning that there are some things science can't measure.