x1 is a gathering/meeting/assembly/conclave/conference/ congregation/congress/convention/encounter/get-together/reunion of participants x2 at location x3 from locations x4.
x1 wears 'on' (Japanese term) on x2 due to x3; x1 is thankful/feels obligation/owes to x2 due to x3; x2 is kind/grants favor/offers 'on' to x1 in x3; x1 has unpayable debt to x2 for x3; x2 is an 'onjin' (benefactor, Japanese term)