When Corporate assigns a Dimensional Investigator to find out what happened to one of their own, afraid for her life, Dani Norris tells her boss a secret. A secret about Dani's sister Marie.

Now the clock is ticking and Dani and Marie must help Ro Parks hide something in the only place where the Investigator can't find it: Yeddoun.

Because she can't trust Ro, instead of putting something in the other dimension, Dani takes something from it: Ulik, the Sentinel Ro Parks pushed into Yeddoun. And he's become one of the monsters they are all working to keep out of earth.

Now that she knows how dimmers are created, Ro tries to force Marie to work with her in order to save other Sentinels

But Marie is not willing to give up her dream of being a doctor and she lures Ro into a trap.

Now it's up to Dani to convince Marie that they need Ro Parks to keep them safe from Corporate.

Can Dani actually save Ro? And should she?