The Enigma Easter Series involves repeated laps of Caldecotte Lake in Milton Keynes, offering traffic-free running and race options across the Easter weekend. Enigma Running organizes marathon and half marathon races on Good Friday and Easter Saturday, with an Easter 5km scheduled for Easter Sunday. The primary location is near the Premier Inn on Lakeside Grove in Caldecotte, with the event centered on the lake rather than on closed city streets.
The course follows a multi-lap circuit around Caldecotte Lake, ensuring ease of navigation and keeping runners clear of traffic. Marathon participants can select either a standard marathon or a 50 km distance, while half marathon runners have options on both Good Friday and Easter Saturday. The Easter Saturday half marathon is presented as an Easter-themed event, and all participants receive custom finisher medals. Route details and course maps are provided at registration, and a mandatory briefing occurs just before each race begins.