“Crossing Over” is episode five of season four of Eureka.
Claudia Donovan from Warehouse 13 is visiting Eureka (this is a cross over episode, not a guest star, hence one reason for the name) and Fargo is more than a little excited, as he’s rather struck on her. Jo is living with Carter after Larry accidentally blew her house up in the previous episode, “The Story of O2”. Henry and Grant are seeing if they can use the bridge device to research wormholes, even if the wormhole to the past has now collapsed.
Claudia initially finds Eureka a little low key – until fully grown redwood trees appear in Global Dynamics’s rotunda. This is followed by a 50 calibre bullet, which materialises inside Jo (ouch!) – and a P-38 fighter plane which appears inside Cafe Diem.
All these items date from the 1940s, which suggests that they are more than a little connected to the trip to 1947 in “Founder’s Day”. It seems that 1947 Eureka is merging with present day Eureka (hence the other reason for the episode’s title). Not good, especially as 1947 Eureka was a military base, rather than a civilian town built around a defence contractor, with lots of dangerous things in it. Like warplanes and guns.