Each year from late March to early April, large migrating flocks of egrets and herons arrive in north eastern China from Japan to mate, nest and rear their young. EGRET is an in-depth lifecycle study of the behaviour of one group of these spectacular birds. Over the course of about 10 days, they settle into the canopy of a mountain forest, where they'll remain until autumn. In all, over a thousand egrets and herons become neighbours in a high-rise bird colony of sorts. Conditions are jam-packed and rival birds of both species cohabit in the trees but fight over available nesting space. Late snowstorms and high winds here also pose threats to their precarious mountain-treetop nests. Before they take to the skies for their return migration, the colony will confront and overcome the numerous dramas of life and death.