We conducted a case study of one of the 70 µm dark high-mass clumps, AGAL023.477+0.114, also known as IRDC 18310-4. Owing to the absence of any bright infrared point source at wavelengths shorter than 100 µm and the lack of molecular outflows in previous observations, this region has been considered a candidate prestellar clump. Using deep, high-resolution ALMA observations, we revealed numerous embedded cores and a remarkable filamentary structure in the dust continuum. We also detected clear signatures of ongoing star formation for the first time in this clump. This chapter demonstrates ALMA’s ability to probe the earliest stages of high-mass cluster formation. It characterizes the physical and chemical properties of the identified cores through continuum and molecular-line analyses, which lead to the classification of their evolutionary stages.