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Massive stars have dramatic impacts throughout the universe comma but their birth comma deep within dusty molecular clouds comma is literally shrouded in uncertainty. However comma during this process comma powerful outflows blast open low density cavities and NIR light shines out from the forming star comma beamed as if from a lighthouse through turbulent storm clouds. This light carries crucial information that can guide us to a deeper understanding of massive star formation. We propose WFC3-IR observations of 10 high-luminosity protostars comma selected to already have well-studied properties via MIR-FIR data. The sources comma along with 5 others with archival HST images comma form a sample to be analyzed uniformly with the following goalsdoublePoint 1) Characterize J and H band continuum emission from massive protostars comma including faint comma extended emission. Radiative transfer simulations show such NIR emission is mostly scattered light emerging from outflow cavities comma thus enabling measurement of their structure comma radiation fields and dust content 2) Detect Pa-beta and CORCHETE_OPENFeIICORCHETE_CLOSE emission tracing shock- and photo-ionized regions comma important diagnostics of the protostars and their outflows 3) Search for low-mass stars that may be clustered around the massive protostars comma as predicted in Competitive Accretion models comma with the observations especially probing in the low extinction outflow cavities. WFC3-IR.s sensitivity comma angular resolution and field of view are essential for this study. The project allows a first exploration of correlations of outflow and cluster environment properties with basic protostellar parameters comma e.g. comma mass comma luminosity and evolutionary stage comma and thus enables groundbreaking tests of massive star formation theories.