  G351.776-0.527 is among the most massive, closest, and youngest filaments in
the inner Galactic plane and therefore it is an ideal laboratory to study the
kinematics of dense gas and mass replenishment on a large scale. In this paper,
we present far-infrared (FIR) and submillimetre wavelength continuum
observations combined with spectroscopic C$^{18}$O (2-1) data of the entire
region to study its temperature, mass distribution, and kinematics. The
structure is composed of a main elongated region with an aspect ratio of $\sim
23$, which is associated with a network of filamentary structures. The main
filament has a remarkably constant width of 0.2 pc. The total mass of the
network (including the main filament) is $\geq 2600$ M$_\odot$, while we
estimate a mass of $\sim 2000$ M$_\odot$ for the main structure. Therefore, the
network harbours a large reservoir of gas and dust that could still be accreted
onto the main structure. From the analysis of the gas kinematics, we detect two
velocity components in the northern part of the main filament. The data also
reveal velocity oscillations in C$^{18}$O along the spine in the main filament
and in at least one of the branches. Considering the region as a single
structure, we find that it is globally close to virial equilibrium indicating
that the entire structure is approximately in a stable state.
