  We revisit a propagating torsion gravity theory obtained by introducing a
field coupled to the Holst term in the first-order Einstein-Cartan action. The
resulting theory has second order field equations, no adjustable coupling
constants, and one more propagating degree of freedom as compared to general
relativity. When no fermions are present the theory is known to be equivalent
to that of a single massless scalar field canonically coupled to gravity. We
extend this result to the case with fermions and obtain an effective
interaction between the scalar field and the fermionic currents. We also
describe a version of the theory with a potential for the scalar field and
discuss whether it can be interpreted as the inflaton.
