  Understanding where and when the mass of stars is determined is one of the
fundamental, mostly unsolved, questions in astronomy. Here, we present the
first results of GASTON, the Galactic Star Formation with NIKA2 large programme
on the IRAM 30m telescope, that aims to identify new populations of
low-brightness sources to tackle the question of stellar mass determination
across all masses. In this paper, we focus on the high-mass star formation part
of the project, for which we map a $\sim2$ deg$^2$ region of the Galactic plane
around $l=24^\circ$ in both 1.2 mm and 2.0 mm continuum. Half-way through the
project, we reach a sensitivity of 3.7 mJy/beam at 1.2mm. Even though larger
than our target sensitivity of 2 mJy, the current sensitivity already allows
the identification of a new population of cold, compact sources that remained
undetected in any (sub-)mm Galactic plane survey so far. In fact, about 25% of
the $\sim 1600$ compact sources identified in the 1.2 mm GASTON image are new
detections. We present a preliminary analysis of the physical properties of the
GASTON sources as a function of their evolutionary stage, arguing for a
potential evolution of the mass distribution of these sources with time.
