Tai-kwan and Keung are estranged brothers who both worked as firefighters but Keung retired 4 years ago and and now operates a fire protection systems company while Tai-kwan has submitted his resignation letter recently. When a serious fire incident happens in a busy commercial tower where Tai-kwan's wife is for work, Tai-kwan sends his unit to help while Keung tries to save his sister-in-law.