Following his confrontation with the nefarious DOA organization, Ken (Chow Yun Fat) is looking forward to going back to enjoying his retirement. His rest is cut abruptly short when his protégé Vincent (Shawn Yue), who's now working for Interpol, asks for Ken's help in taking down the real mastermind behind DOA, Aoi. The two head to Thailand, where DOA's former chief accountant Mark (Nick Cheung) has escaped with his daughter.
As humanity picks up the pieces after the battle of Chicago, a shadowy group reveals itself in an attempt to control the direction of history…while an ancient, powerful new menace sets Earth in its crosshairs. With help from Cade Yeager, Optimus Prime and the Autobots rise to meet their most fearsome challenge yet.