There was severe traffic congestion in the Caerphilly town area after an accident on the A469.
The accident happened near Hendre Junior School in Trecenydd and closed the A469 between the St Cenydd and Pwllypant roundabouts.
A Gwent Police spokesperson said: “Gwent Police were called at approximately 4.10pm on August 25 to reports of a RTC on the St Cenydd Road near St Cenydd roundabout.
“Officers attended the scene and dealt with a four vehicle collision which included a motorbike.
“One male person has been injured who has suffered serious injuries.”
Anyone who may have witnessed the incident can call Gwent Police on 101.
The road reopened at 9pm.