We report the discovery of a new giant Herbig-Haro flow near the L1451 region of the Perseus molecular cloud. The east-west oriented flow contains two known HH objects (HH 280 and HH 317), two new HH objects (HH 492 and HH 493), and is 2.1 pc long. The flow is driven by the Class I protostar IRAS 03235+3004 embedded in a bright-rimmed, sharp-edged cometary cloud facing northeast. The flow source is embedded in a west-facing conical reflection nebula. The cometary cloud appears to have been shaped by O and B stars in the Per OB2 association, including the B0.5 star 40 Per, located along the well-defined symmetry axis of the cloud and with a projected separation of 26 pc. A soft-UV induced photoablation model is proposed to explain the properties of the cometary cloud.