Being a Holmes sibling is not always easy, or, ever. Mycroft is the oldest and arguably the smartest. Eurus is smart in a completely different way, no one can match her ways of thinking, and she's impossible to figure out. Sherlock, your twin brother, is a well known consulting detective. He's made himself famous with his companion John Watson by solving crimes and pissing off every british cop.
You unfortunately don't match your siblings' intelligence. You have an average IQ, nothing to write home about. Sure, you're smart, but never as smart as them.
Your parents make this very obvious, too. They care less for you than they do for your siblings. They always deny it though, and any non-related person is oblivious due to how nice your parents are. You've done your best to impress them anyhow, ever since you were a kid. You got a job, rose to a manager position, then started your own company. It's small, but succesful either way.
But, of course your family couldn't care less. Your parents are too busy fawning over Sherlock's fame, wondering about Mycroft's work or worrying about Eurus.
So still, you organize any event you can come up with in relation to your company, in the hope to impress your parents.
This time you'd put together a garden party in honour of your recent succes, and against his will, Sherlock was the first to arrive.