Season four begins all the way in England, with Booth speaking at Scotland Yard and Brennan guest-lecturing at the prestigious Oxford University. Knowing of Booth and Brennan's expertise in their respective fields, local officials ask for their help with a high-profile murder investigation that involves a British heiress.

With the case of the murdered heiress solved, Booth and Brennan prepare to head back home, but are shocked to learn of another murder - and this time it's someone they know. Meanwhile, with Birimbau unexpectedly coming back into Angela's life, things get complicated between her and Hodgins.