One of the most common reasons for a valve to keep running continuously is the accumulation of debris in the diaphragm, which prevents the valve from closing. This video will teach you how to clean the diaphragm on your valve.
There are two reasons why your sprinklers would continue running with controller unplugged:
It's possible your valves have been opened manually. You'll need to locate your valve box(s) and turn the solenoid(s) clockwise until snug. The solenoid is located on the top of the valve and looks like a cylinder with two wires protruding out of it.
It's also possible that there is debris in the valve, which is causing the diaphragm of the valve to remain open.