The team travels to the UK amid reports that a high-ranking US Navy rear admiral on vacation in London has been killed in a multiple fatalities asteroid attack.
However at a Top Secret briefing officials suggest the deaths, including the US two-star flag officer's, might actually be due to a sexually transmitted disease.
Of course Gibbs is skeptical and insists his Chief Medical Examiner Dr Donald 'Ducky' Mallard screwtinises all the data.
A few hours later a very excited Ducky emerges waving CCTV footage of the original autopsy.
'I think I've cracked it, Jethro,' the doctor chuckles, 'and just as I suspected you can blame the misdiagnosis on a typical language snafu.'
The footage shows Brit pathologists discussing the headcount of the wounded, the dying and the already RIP'd:
'Them two is dead, Guv, but this one 'ere's still twitchin', a cockney morgue assistant tells his boss pointing to the rear admiral as the bodies continue stacking up.
'Better make a note of that, young man,' the pathologist replies, 'it's important we get it right.'
'Can you play the rear admiral's cause of death diagnosis, Ducky?' Gibbs asks.
Dr Mallard quickly fast forwards the video tape and presses the button to demonstrate the sidekick's bizarre prognosis:
'Take a raincheck on that twitchin', Guv,' the assistant remarks, 'reckon we've got another goner 'ere.'