Abstract: A flush bolt mechanism is disclosed for latching the inactive one of a pair of swinging doors, the mechanism functioning to latch the closed inactive door in response to closing of the other door. The latch mechanism includes a bolt that is driven home by cam and spring assemblies. A heat-responsive mechanism is provided for retaining the bolt in its extended position when the heat-responsive mechanism is subjected to a temperature and for a time sufficient to melt one of its components. A release mechanism may be provided for retracting the extended bolt in response to a force of preselected magnitude applied against the inside of the inactive door.