  The Kepler Space Telescope has discovered thousands of planets via the
transit method. The transit timing variations of these planets allows us not
only to infer the existence of other planets, transiting or not, but to
characterize a number of parameters of the system. Using the transit timing
variations of the planets Kepler-159b and 159c, the transit simulator TTVFast,
and the Bayesian Inference tool MultiNest, we predict a new non-transiting
planet, Kepler-159d, in a resonant 2:1 orbit with Kepler-159c. This
configuration is dynamically stable on at least 10 Myr time scales, though we
note that other less stable, higher-order resonances could also produce similar
TTVs during the three-year window Kepler was in operation.
