The male leads are trapped in my house (TMLTMH)

I reincarnated as the heiress of a powerful conglomerate family in a novel. The problem is, this world is about to be destroyed by monstrous viruses. With nothing but money to spare, I quickly bought a mansion in the countryside to build a shelter to escape the monsters... But the world ended far sooner than I had anticipated. Damn it! * On top of that, somehow, the male leads ended up trapped in my house with me. And these guys don't seem to have any intention of leaving. Why do they look like they have no plans to go to the female lead? "Who exactly are you?" "You seem like someone who knew the world was going to end beforehand." They were full of questions about me, but I couldn't answer them. They wouldn't believe me anyway. Right now, all I see them as is a good source of labor. "Alright, let's work. You need to earn your keep for what you eat!" If I can find the cure for the virus causing the apocalypse, this hellish time will finally end. So, until then, I'll make use of the male leads and hang on! * But one problem has come up. It turns out that this old mansion I purchased is far more suspicious than I thought. What on earth is happening in my house?