The Shadow Word is where the Mondays come from. To see more click here. It is the opposite world of the saturdays world. It was mentioned in Black Monday, at the Mondays' first appearance. They wanted to send the Saturdays there. Zak Monday mentioned, that locals didn't like them there and as Drew mentioned there's no hot chocolate. It was seen in Paris is Melting. Zak Saturday went here to get the Monday's Airship in his world, for his brothers and sister's freedom. The rest of the Monday family captures Zak, but he made a deal with them: he sends back Zak and Komodo Monday, for his own freedom. But before he went back, he drained the energy, and because the Saturdays get the energy from the Sun, the Mondays get it from the darkness, and fortunately as Zak mentioned it was a nice sunny day. The Airship fell back into the Shadow World with Zak and Komodo Monday, where the other Mondays got their revenge on them. It was unknown what happened, to the Mondays, since And Your Enemies Closer, when Zak Monday got back in our world with V.V.Argost's help.