The invention relates to a multistage high pressure fracturing system and tubular hydraulic valve (THV) system for connection to a completion string to enable isolation of a zone of interest within a well. In particular, the system enables access to a downhole formation for fracturing the zone of interest and for hydrocarbon production. The system generally includes a plug counting system, a plug capture system and a valve system wherein dropping a series of plugs down the completion string enables successive capture of individual plugs within individual THVs for subsequent fracturing operations.