Katniss is weirded out by President Snow being in her house, to say the least.
She's worried she's in "serious trouble" (2.18). He appears like a snake to her.
They agree to have a straightforward conversation. He makes it clear that if she doesn't cooperate, everyone she loves will be in danger.
He says the stunt she and Peeta pulled in the arena during the last Games made things difficult. The Gamemaker who let them both live through it has been executed.
Snow says not everyone believed Katniss was in love with Peeta, and that she seems to have been taken for a rebel. He is concerned that other people of the districts will also rebel, following her example.
He acts like he cares about the country, but Katniss knows it's not true.
Her mother brings them tea and cookies, which Peeta made.
Snow emphasizes how dangerous Katniss is to the country. She asks him why he doesn't just have her killed, and he says it wouldn't make things any better; she'd look like a martyr for the cause.
Snow makes it clear he knows Katniss was pretending to be in love with Peeta and threatens Gale's life.
Katniss realizes how little private time she's had since winning the Games. District 12 has been full of cameras. It sounds like she's been observed even in the woods, which she'd thought of as her private sanctuary.
When she first returned from the Games, she went out to the woods and Gale finally met her. They had an emotional reunion and he kissed her – just once.
Afterwards, they never mentioned it, and Katniss thought no one knew about it.
Katniss tries to assure Snow that she and Peeta are still in love, and she'll make everyone on the tour believe it.
Snow says she has to make him believe her, and that he knows about her and Gale. Then he leaves.