The relaxation mechanism of the overtone bending vibration in the collision of the water dimer with the vibrationally excited hydroxyl radical is studied by use of trajectory procedures. The transfer of the OH(v = 1) energy to the dimer stretches is followed by a near-resonant first overtone transition to the donor monomer. Nearly a quarter of the trajectories undergo a complex-mode collision, forming the (H2O)(2)center dot center dot center dot OH complex bound by a hydrogen bond with the lifetime ranging from a subpicosecond scale to >100 ps. The overtone vibration relaxes to the ground state, transferring approximately half of its energy to the dimer hydrogen-bonding (H2O center dot center dot center dot H2O) and the remaining half to the complex hydrogen-bonding (H2O)(2)center dot center dot center dot OH, via near-resonant pathways, each consisting of a series of intermolecular low-frequency vibrations.