Through large-scale surface hopping simulations with a vibronic coupling model including electrostatic embedding, we have gained unprecedented insight into the ultrafast solvent response around photoexcited [Fe(CN) 4 (bipy)] 2-. The solvent mechanism can be summarized as follows. In the electronic ground state, water forms rings of hydrogen bonds around each of the four negatively charged cyanide ligands, and only a very weak solvation shell around the bipyridyl ligand. After excitation to a bright 1 MLCT state, water recedes from the axial and equatorial cyanides with 50-75 fs time constants, even before ISC to the 3 MLCT and 3 MC states has taken place. On a few-hundred fs time scale, the water molecules detached from the axial cyanides migrate to a position above/below the bipyridyl aromatic system, forming hydrogen bonds to the ligand that has increased electron density in the MLCT state. This constitutes a directed hydrogen bond migration mechanism without substantial involvement of bulk water. In contrast, water molecules recede from the equatorial cyanides into the second solvation shell to accommodate the changes in Fe-CN bond lengths.