A hybrid drive system in a vehicle includes a prime mover, a starting device connected to the prime mover, and a transmission having a transmission input shaft connected to the starting device. A pump/motor is functionally interconnected between the starting device and the transmission. A first accumulator is in fluid communication with the motor/pump for storing a hydraulic fluid under pressure and a second accumulator is in fluid communication with the pump/motor for storing hydraulic fluid discharged from the first accumulator. Discharge of the first accumulator drives the pump/motor to provide a drive torque to the transmission input shaft and to provide a drive torque to the prime mover for starting the prime mover.