In 1968, a Czech doctor with an active sex life meets a woman who wants monogamy, and then the Soviet invasion further disrupts their lives.

Tereza: I know I'm supposed to help you, but I can't. Instead of being your support I'm your weight. Life is very heavy to me, but it is so light to you. I can't bear this lightness, this freedom... I'm not strong enough.
Tomas: You can sleep. Sleep in my arms. Like a baby bird. Like a broom among brooms... in a broom closet. Like a tiny parrot. Like a whistle. Like a little song. A song sung by a forest... within a forest... a thousand years ago.
Tereza: I don't understand how someone can MAKE love without BEING in love.
Tomas: I must go.
Sabina: Don't you ever spend the night at the woman's place?
Tomas: Never!
Sabina: What about when the woman's at your place?
Tomas: I tell her I have insomnia... anything. Besides, I have a very narrow bed.
Sabina: Are you afraid of women, Doctor?
Tomas: Of course.
Sabina: I've met another man. He's the best man I've ever met. He's bright, handsome and he's crazy about me. And, he's married. There's only one thing; he doesn't like my hat.
Sabina: I really like you, Tomas. You are the complete opposite of kitsch. In the kingdom of kitsch you would be a monster.
[last lines]
Tereza: Tomas, what are you thinking?
Tomas: I'm thinking how happy I am.
Tereza: I was forced to love my mother, but not this dog. You know, Tomas... maybe... maybe, I love her more than I love you. Not more. I mean in a better way. I'm not jealous of her. I don't want her to be different. I don't ask her for anything.
[first lines]
First Title Card: In Prague, in 1968, there lived a young doctor named Tomas...
Tomas: Take off your clothes.
[line recurs several times during film]
Tereza: [referring to her dog] Karenin prefers Mephisto to dogs. She thinks other dogs are silly.
Tomas: [Mephisto snorts and Tomas inhales the aroma of the food] Ha-ha.
Pavel: Do you know why I love Mephisto? Because he's very bright, but, at the same time,
[gesturing for emphasis]
Pavel: he doesn't know anything! After all, he doesn't know that life is impossible here now. Nothing left here. The church is gone.
[shrugging]
Pavel: No place to drink beer now.
[he drinks his bottle of beer very quickly]
Pavel: It's good... very good.
[slurping]
Pavel: If you ever change your mind, it won't be easy to leave.
Sabina: Take off your clothes.
Tereza: [taken aback] What?
Sabina: [taking the camera] Now it's my turn.
Tereza: [backing up] I don't like to be naked. I...
Sabina: [insistent] Take off your clothes!
Tereza: Wait!
[she ducks behind the bed]