What if...?

What if I wrote a story that was about the children of an immortal through the ages? Like, their dad is immortal and they are mortal but they can't have regular families of their own so they just sort of... find each other across time and space and band together. And then they form some sort of vaguely dysfunctional and ill-defined sibling-slash-parent relationship where the older kids mentor the younger ones and show them the ropes of being demigods. Or something.

Or what if I just stuck to the writing goals that I've already set for myself.