I-5 is on alert when a report from the UK Border Agency reveals that a highly sophisticated Chinese hit team has entered the country. The CIA station chief says they know of no reason why the team might be in the UK and MI-5 determines that their interest is likely a British-designed water desalination system. Beth has been working on turning a Chinese Embassy employee but her rushed effort leads to failure, at least initially. Ruth Evershed goes into the company undercover only to find that the CIA is involved and protecting the scientist who developed the new desalination process. When the Chinese station chief threaten to set off a bomb n central London, Harry must decide whether to let them have the scientist or face down their threat. Lucas meanwhile struggles to keep his past a secret.

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