Warehouse 13 is set in the same world as Eureka and Alphas and one of the characters from Warehouse 13 does appear in an episode of Eureka (not Saul Rubinek, who plays Artie; although he appears in the Eureka episode “Invincible”, it’s as a different character. He also appears in Heroes: Part 1 and Part 2 in Stargate SG-1) and one character also appears in Alphas. Some of the actors from Eureka also appear in Warehouse 13 – but not in their Eureka roles – presumably those episodes were filmed prior to the decision to have the various series being set in the same world, but one does also appear as the same character in both Eureka and Warehouse 13, Douglas Fargo.
The Warehouse is the latest – number 13, naturally enough – in a series of warehouses where artefacts are stored, warehouses which go back many years. Artefacts are potentially extremely dangerous, and powerful, items; although artefacts that play a role in the series are linked to famous people, this does not have to be the case. Artefacts can affect their possessor, or their environment, and these effects are often not entirely beneficial top their user, or those affected. Death, in many different forms, is a common feature of the series; often the first sign that the Warehouse team gets that an artefact is causing problems is when unusual and bizarre deaths are discovered.
Warehouse agents have access to sometimes primitive-looking high technology; namely, items that were invented much earlier than their mainstream variants and so used much more primitive components, such as black and white video communicators from the 1920s and mechanical computer cracking devices.
The stories involve the agents recovering these artefacts, but such powerful items also have value to others, and so they are not always the only people looking for them. Many of the episodes are standalone, but there are often multi-episode plots, which tend to be connected to those after artefacts for their own purposes, from individual ones to the entire Warehouse. The hazards in the initial episodes primarily come from the artefacts, but as the series progresses this becomes less the case. The artefacts are still dangerous and frequently spread death and destruction, but it’s the hands of those other than Warehouse agents that the true danger comes from, as they wield artefacts in order to achieve their own goals. There is rather more of a fantastic feel to the series than would be seen in Eureka, with its futuristic technology; despite the protestations of one of the characters, the artefacts have a more magical than technological feel to them.
Warehouse 13 ran for five seasons, with season four having a significantly higher number of episodes, twenty to the thirteen of each of the previous three, with a midseason finale, and season five a significantly lower number, with only six. The final episodes of seasons two and three were essentially Christmas specials, having no continuity connection to the previous episode, or the first episode of the next season.