We open with Justin Quayle, a mild-mannered British diplomat, saying goodbye to his wife Tessa at an airfield. She is flying off with a colleague, Mr. Bluhm, and expects to be back in a few days. Cut to Justin meeting with his boss and taking care of the plants because he cannot help himself; he's told that Tessa may have been killed.
Cut without warning to Justin and Tessa's first meeting. Justin is filling in for a higher-up diplomat, Sir Bernard Pellegrin, at the UN; Tessa uses the Q&A to go after him, the positions in the speech he read, and British foreign policy. When it is suggested that she be kicked out, Justin argues that her points are valid; she goes even further until she and Justin are the only people in the room. Justin secretly agrees with her, of course. They go out to dinner...
Cut to the present. Justin and his boss are in a morgue. A burned body lies under a sheet, and Justin is asked to ID it. It's Tessa; there is a Gory Discretion Shot, but we do get to see Justin's boss, Sandy, vomit a little. Justin hangs back and remembers his life with her...
Flashbacks. When Justin was sent to Africa, Tessa wanted to go. We do not see how the scene she requests this ends because we know the answer because this is a flashback. Once in Africa, Tessa hooks up with an international medical agency and tries to push her positions to other people. She does not do diplomacy well. Justin has promised to protect her, but has also promised not to interfere with her work; when she gets into compromising-looking positions with her medical coworker, he has trouble keeping the promise and sinks deeper into gardening. She does a lot of computer-work, and severely objects to his insecticide at one point. But she tries to protect his innocence.
She gets pregnant. She refuses to stop working even when she's at risk of giving birth in a bad part of Kenya; when she does, the baby is stillborn. The clinic she is at tries to give her special treatment, but she cedes the bed to another woman. She wants to drive that woman's family home, because they're from a long way away and they walked; Justin says that there are too many and he wants her safe, and so he doesn't give them a ride. He will regret this later.
She demands that Sandy do something when she gives him a report. It gets kicked upstairs, and a personal letter got kicked back down. She asks to see the letter; because he's pressed for time, the boss agrees to this as long as she puts everything back and has sex with him when she gets back from the business trip she didn't come back from.
Finally, we see his farewell to her again.
When he comes home, he learns that her personal things have been rummaged through. Her computer, CDs, and many of her papers have been stolen. But they didn't find a hidden memory box, and Justin finds two empty giveaway medicine boxes—one with writing inside—for an experimental medicine. He also finds a letter from his boss which complains that she has something of his that he didn't agree to give her, but he's looking forward to sex... This shakes Justin.
A funeral is held for Tessa; she is to be buried in African soil. Justin forbids the natives from adding concrete because concrete is not soil. The son of the woman whom Tessa gave her bed to leaves a card (on another free medicine card), but doesn't want to talk to Justin.
Justin goes to find the woman. The clinic has no records of the woman at all. He meets her son at the medicine line and finds that the natives can get medical care only if they get the experimental drug. He is then arrested for looking.
Justin is now investigating things which Tessa was protecting him from, since he was a sweet, innocent, lovable diplomat. But he cannot let this go. His superiors try to stop him in various ways, using the official excuse that he's no longer mentally stable. And, in fact, he is no longer mentally stable. But people are still out to get him....