Dethroned

Someone always takes the crown. Here is who ruled the UK Singles Chart — the week's #1 by Power Index, which is not always the #1 single — and for how long. Pick who took over, from four acts from that week; their songs are the clue, and each has a clip. Follow the chain forward through history. Three strikes and the chain ends, but the story carries on after a miss, so you always learn who it was.