bluebird of happiness

noun1

1. •
   Happiness or contentment, especially as the elusive object of a quest or as a state of affairs which is difficult to achieve.

   • Tora (Kiyoshi Atsumi), our feckless itinerant peddler, dreams he's leading his relatives in a pursuit of the bluebird of happiness, which takes them to a veritable Shangri-La. — 1987