Here, we report a tetrahedral silver(I) cluster of {Ag4}4+ covered by Δ-[Rh(l-cys)3]3- (l-H2cys = l-cysteine), which is converted to an {Ag4H}3+ cluster via the inclusion of a H- ion. The 1:1 reaction of Δ-[Rh(l-cys)3]3- with Ag+ gave a sulfur-bridged AgI4RhIII4 octanuclear structure in [Ag4{Rh(l-cys)3}4]8- ([1]8-), in which a tetrahedral {Ag4}4+ core is bound by four Δ-[Rh(l-cys)3]3- units through thiolato groups. DFT calculations revealed that a superatomic orbital exists in {Ag4}4+ as the lowest unoccupied molecular orbital, contributing to the appearance of a characteristic charge-transfer transition in the visible region for [1]8-. Treatment of [1]8- with NaBH4 led to the insertion of a H- ion to generate [Ag4H{Rh(l-cys)3}4]9- ([2]9-) with an {Ag4H}3+ core, accompanied by the disappearance of the visible band for [1]8-. The presence of a H- ion in the center of [2]9- was established by the 1H NMR spectrum, which reveals a unique quintuple-quintet signal from the H- ion surrounded by four AgI atoms. [2]9- was considerably stable in aqueous media, which is ascribed to a chemical bond between the unoccupied superatomic orbital of {Ag4}4+ and the occupied orbital of H- in the {Ag4H}3+ core.