  We present new observations of the ultra-compact HII region G28.20-0.05 in 23
GHz continuum, and the NH3(1,1), NH3(2.2), and NH3(3,3) lines. To explain the
complicated kinematics of the molecular gas, we propose a model consisting of
two components. One component is an infalling, equatorial torus of molecular
gas, whose dense central region has been ionized to form the ultra-compact HII
region. The second component is a larger expanding molecular shell driven by
some type of wide-angle outflow or wind. We estimate that the infall component
includes more than 18 Msun of molecular gas. We calculate the central mass to
be 79 Msun, probably comprising more than one star. The arrangement of the
molecular material suggests a connection to the other disk-like structures seen
around massive young stars. The central star in this case is more massive, and
the whole region may be more evolved than other similar objects such as IRAS
20126+4104, IRAS 18089-1732, G192.16-3.84, and AFGL5142.
