Work Text:
Peter Allen is the grandson of Barry Allen aka the flash and Isabella Kent is the granddaughter of Clark Kent aka superman and they both went to superhigh a high school for superhero kids.
It all started when Isabella got shot with a kryptonite bullet and Peter phased his hand through her chest and removed the bullet it was at that moment that they fell in love.
They didn't tell each other till one day Isabella used up all her solar radiation temporarily lost her powers but Peter refused to leave her in this state and when she asked why he said it was because he loved her. Just then she kissed him then whispered something in his ear and he ran them to his dorm and locked the door...