  We present preliminary results achieved within a recently started project
dealing with QCD thermodynamics in the presence of a fully dynamical second
quark family. We are employing the Wilson twisted mass discretization. To
reduce the amount of zero temperature simulations and the cost of analysis we
have chosen the fixed-scale approach. We show a variety of basic thermodynamic
observables for temperatures ranging from 158 to 633 MeV. Simulations were
performed for three lattice spacings below 0.1 fm each and at a single value of
the pion mass which allows a comparison with previously obtained $N_f=2$
results. We determine the chiral crossover temperature from the bare chiral
susceptibility and show results for the gauge part of the trace anomaly.
