The disclosure relates to a heat exchanger, for example an indirect air cooler, in which the air, for example compressed charge air for an internal combustion engine, is cooled, for example by a fluid, wherein the heat exchanger is constructed from stacked pairs of plates. The exemplary fluid can be conducted into an inlet region and/or outlet region of the plate pairs in at least one flow path approximately in the direction of the common edge, and further through at least a first duct approximately in cross current with respect to the exemplary air, and passes further through the plate pairs over the largest heat exchange area of the plate pairs approximately in countercurrent with respect to the air, in order to flow through at least one second duct, approximately in cross current with respect to the exemplary air, and back to the outlet.