#50 narrated by Cassie! Cassie and Jake have always been together. Made for each other. Leader and advisor. But everything's different now. They don't seem to know how to relate to each other anymore. The only thing they can think about now is trying to survive long enough to stop the Yeerk invasion.

Despite trying to deal with all the changes in her life, Cassie has managed to come up with a plan. A daring and dangerous plan. A necessary plan. The Animorphs go for it, despite the risks. Only one problem -- the Yeerks. They want the blue morphing cube. Cassie has to make a choice. Let them have it -- or watch Jake die...