It's not normal?

All throughout his time at Hogwarts Harry constantly received letters containing thinly veiled threats from his uncle. He never truly let hope blossom, knowing his fate when he returned home.
But it never bothered him that much.

It was normal to eat barely anything. He had to be thin to be pretty!
It was normal to do all the house work. He needed to earn his keep and their love.
It was normal to sleep on a bedroll in a cupboard. His bad behaviour meant he needed to be punished.

So when he began dating, why would it be any different?

It's only when one night goes too far, leading to a stay at St. Mungos, that someone comes forward save Harry.
The person who had sworn to protect him since that fateful Halloween night.

Severus had seen in The Daily Prophet that Harry was in the hospital. Honestly that newspaper had no compassion for the war hero'a privacy. Nevertheless, in this instance he was thankful for the nosy reporter.

While it wasn't that Harry was in St Mungos that grabbed his attention, it was some of the details surrounding the circumstances of his hospitalisation that were concerning.
The boy hadn't been on an auror mission or even training. Even so, it was hardly ever this bad from what he could recall of previous articles and local gossip.
Neither had he been attacked somewhere.

So what had happened to him?

Severus needed to find out. He owed the boy a life debt (from Nagini) and an oath for his mother.