Here, we report a tetrahedral silver(I) cluster of {Ag-4}(4+) covered by Delta-[Rh(L-cys)(3)](3-) (L-H(2)cys = L-cysteine), which is converted to an {Ag4H}(3+) cluster via the inclusion of a H- ion. The 1:1 reaction of Delta-[Rh(L-cys)(3)](3-) with Ag+ gave a sulfur-bridged Ag-I Rh-4(4)III octanuclear structure in [Ag-4{Rh(L-cys)(3)}(4)](8-) ([1](8-)), in which a tetrahedral {Ag-4}(4+) core is bound by four Delta-[Rh(L-cys)(3)](3-) units through thiolato groups. DFT calculations revealed that a superatomic orbital exists in {Ag-4}(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 H-1 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 {Ag-4}(4+) and the occupied orbital of H- in the {Ag4H}(3+) core.