With Natasha gone for a three month mission, Steve, Clint, and Bruce/Hulk write her letters without letting each other know. Sometime Tony would write when he's feeling horny and alone while his Pepper is out and about with meetings. As time goes there will be more pop ups with other members that seems to notice Natasha's disappeance and raged along with the writing to the Assassin. Turning into a One Shot letters