Complex sentence: When Doc and Jerry learn the truth the agent hijack Doc's aeroplane with the two girls as hostages, however Doc's plane has the remote control device that works and Doc and Jerry are able to land the plane and capture the agent.
Split into simpler sentences: When Doc and Jerry learn the truth the agent hijacks Doc's aeroplane with the two girls as hostages. However Doc's plane has the remote control device installed that now works and Doc and Jerry are able to land the plane and capture the agent.