In this letter, we propose a system for through-wall imaging based on a bistatic setup and a two-step inversion procedure. Since the adopted configuration is simple and low cost but only delivers a limited amount of data, the data-processing stage is tackled in a stepwise fashion. First, the targets are detected from the estimation of the surface impedance along the wall and then the area behind the identified portion of the wall is imaged by means of a linearized microwave-tomographic algorithm. The overall device is described, and the results of a proof-of-concept experimental validation are reported.