A vapor-generating system includes a cartridge, a vapor-generating device and a piercing element. The cartridge includes a cartridge housing configured to hold a solid vapor-forming substrate within the cartridge housing interior, a liquid storage housing configured to hold a liquid vapor-forming substrate within the liquid storage housing interior, and a frangible seal on the liquid storage housing. The vapor-generating device includes a device housing at least partially defining a cavity, an electric heater, and a power supply. The piercing element is configured to pierce the frangible seal of the cartridge to expose the liquid storage housing interior to be in fluid communication with the electric heater based on the vapor-generating device coupling with the cartridge such that the device housing at least partially receives the cartridge into the cavity. The electric heater is located externally from the piercing element.