Torchwood - Ep Related - Small World - Jack once told Gwen that he doesn't sleep. She never questions it, but in Small World we see him sleeping, experiencing a nightmare involving the fairies. A nice lead into the story line...and also a nice peek into Jack's secret fears. Also leads us into this challenge as it happens.
I heard, or read, from some source or other, probably a dvd clip or what-not, that Jack is actually afraid of the fairie-folk. Well, who can blame him.
In "The Torchwood Archive" ongoing archive notes (Jack Harkness page) he states that after the case only Ianto, just back from a 14 day suspension from the Lisa fiasco, is still talking to him (Jack). The challenge this time....Let Ianto catch onto Jack's on-going and increasingly terrifying nightmares, and deal with his own conflicting feelings with Lisa's death as he comes to terms with how to help Jack deal with his issues, if he is willing to help him at all in his own fragile state of mind. related pairing - Jack/Fairie (don't kill me, I'm feverish, remember)
*Second Pairing alternative okay, so as long as you use Jack/Ianto in the pairing, you're good to use your favorite other pairing for whatever purpose pleases you