On 4th July 2012 it was announced that the world's most-wanted particle - the Higgs boson - had been discovered. The particle is the fundamental ingredient of the Higgs field, which is supposed to give mass to everything known in the universe. Derek Muller visits the physicists at CERN in Switzerland where they are busily probing this curious new particle in an attempt to reveal its properties. With more data, they hope soon to know what they've found. Of course, if it's not the Higgs, then what is it?