Inspired by a true event, the story of Assembly begins in 1948, right at the high point of the bloody civil war of China. A communist-led army captain, Guzidi is ordered to command his 46 men to defend a position by all costs and he is allowed to retreat only when the assembly call was blown. The call never comes and after a horrific fight, the captain finds out he is the only survivor. Without a survivor to vouch for them, the 46 men who had bravely sacrificed their lives under him had simply listed as missing. Determined to prove the glorious death of his 46 men, Guzidi embarked on a journey in search of those who held the key to the mystery of the bugle call.
