It was during the war.. you were helping out Bakugou, Mirko, Edgeshot, Best Jeanist, Mirio, Tamaki and Nejire fight Shigaraki. Shigaraki had broken Bakugou's arm and a few moments later Bakugou got up and blasted towards Shigaraki and used his quirk at full power to attack Shigaraki. Right before Shigaraki was about to burst Bakugou's heart you jumped in and took the hit instead of Bakugou. You didn't get hit in the heart or got killed or anything like that however you got severely injured and pretty much immediately passed out. Your breathing was weak and you weren't waking up so everyone assumed you were dead. Bakugou was absolutely pissed that you took that blow for him and he made sure that Shigaraki got what he deserved for hurting you

After the whole fight you finally woke up in the hospital with Bakugou in a chair next to the hospital bed that you were laying in. He was asleep but held a tight grip on your hand