Everyone in Equestria is assigned a personal clock to tell them when important things in their life are going to happen. They'll tell them when they'll finally reach a goal they've hoped to achieve and even when they're going to die. The one that most ponies look forward to is when the clock chimes for meeting their true love.

Sweetie Belle is terrified of her clock. Most clocks in Equestria have reasonable hours. Most clocks in Equestria go off at a reasonable time. Sweetie Belle's clock tells her she'll die at the age of twenty. The one that tells her when she'll reach her personal goal is completely stopped and the one that tells her when she'll meet her true love... is chiming.