The nature of exciton-plasmon interactions in Au-tipped CdS nanorods has been investigated using femtosecond transient absorption spectroscopy. The study demonstrates that the key optoelectronic properties of composite heterostructures comprising electrically coupled metal and semiconductor domains are substantially different from those observed in systems with weak interdomain coupling. In particular, strongly coupled nanocomposites promote mixing of electronic states at semiconductor-metal domain interfaces, which causes a significant suppression of both plasmon and exciton excitations of carriers.