The first lie, the first real lie, is just one word: "Deceased."
It rolls out of his mouth like he's practised all his life, like the sum of all the lies that came before: broken bone, little bruises, he didn't miss his Mam, he went to school, he loved that film, he didn't cry, that dress is perfect, they can't go to meet his family this year, she's dead. The Captain doesn't doubt him but doesn't care, either. The coffee is a kind of truth, something else to offer if what was on display last night does not appeal.
When next they meet, Ianto wears one lie, buttoned up and tied in a half-Windsor. The big lie is in the warehouse, carefully trapped and trained to respond to food. Despite the ridiculousness of suit and pteranodon, the Captain trusts him. He'd like to believe the moment on the concrete floor to be another lie, feeling Jack's heat, breathing Jack's breath, but it's too close to truth, too raw. Lies leave him with a pleasant buzz, not this gut-churn that makes him sick in the alley when he's far enough for the Captain not to hear.
The lies cascade: power fluctuations, filing in the archives, supplies to order, medicines misplaced. The best lies are the ones the others tell themselves to explain his quietness, his absence from the main level, the hesitancy in his manner when the Captain teases. He allows them their own stories, and keeps to himself.
Lisa is truth, and truth is terrible. Lisa is a killer. Lisa will kill him, kill the people he works with (he's not a good enough liar to make himself believe they are his friends), kill the whole world. Lisa is dead. Lisa died months ago, and he's been carrying her corpse with him ever since.
The cannibals are also truth, and this truth is worse. Robots from outer space kill because they want power. Humans kill because they can. He is unimportant. He is weak. He is meat.
He needs a new lie, and he looks to the greatest liar of them all. No more truth except that he wants this, no more pain except when Jack's hand strokes a bruised rib. Jack's name is a lie on his lips when he comes, and his own name is just as false when Jack follows. Mending Jack's coat, he tells the fiction about his father, and Jack knows because Jack knows everything about him, but he just nods and agrees. If they each know every word is a lie, the words circle back almost to the truth.
Then Jack is lost, and Toshiko is lost, and Owen is more lost than anyone. Ianto doesn't know what to do, so he does what he thinks Jack would want, and he fails. When Jack returns he wants to say, "I failed for you," but that's too close to the truth. Truth is bitter when he sees the distance in Jack's eyes, when he finds out what happened in 1941, when Owen's hurtful words are the biggest reality in the room.
Jack dies, and while Ianto has long understood the power of lies of omission, he never suspected this one. Jack dies again, and truth is cold, pale skin, is the already fading scent of his collar, is Gwen's widow wake in the morgue while Ianto does not even dare one last goodbye. Jack lives, and Ianto is ready for the casual lie of a handshake, not the earth-shaking truth of a kiss.
Jack is gone.
A week passes. Tosh brings him a cup of tea, and sits with him up in the tourist office, the professional lie. "You miss him, don't you?" She's asking to validate her own pain, but it's okay.
"Sometimes," which means "Yes." He is learning her half-truths as she is seeing through his. If he could make himself believe in friendship, he might find faith yet in the steaming mug and her quiet slump of shoulders.
Gwen doesn't come to him with tea. They are the last ones in the Hub tonight after too long of a day. She stands, twisting her new ring. "Do you … did you love him?"
This isn't the time for truth, and the lie is like having Jack home again. He thinks Jack would understand.