We study quantum effects of light propagation through an extended absorbing system of two-level atoms placed within a frequency gap medium (FGM). Apart from ordinary solitons and single-particle impurity band states, the many-particle spectrum of the system is shown to contain massive pairs of confined gap excitations and their bound complexes—gap solitons. Quantum gap solitons propagate without dissipation, and should be associated with self-induced transparency pulses in a FGM.