This lovely story is by
serenelystrange, with a confused Hardison, gruff Eliot, and bouncy Parker all going through the tail-end of their teen years whilst in a foster-care home under Nate and Sophie's care.
Quite possibly my favouite scene from the fic, Parker just jumped onto Hardison's back and demanded a piggy-back.
And of course, the picture that started it off: