Even though I make a point not to like books with returning characters whom everyone thought was dead, (can we say running out of ideas?) The Return was pretty good.
Do you remember David, waaaaaaaaaaay back from the earlier books, the three-part miniseries? After seeing his family captured and home destroyed by the Yeerks, the Animorphs were left with a tough decision. Do they leave him, an innocent kid like themselves who happened to be in the wrong place at the wrong time, to become another Controller? Or, now that they have the blue box, Elfangor's morphing cube, do they make him one of them? A human with morph capabilities . . . an Animorph.
As you know, they chose the latter, and the small band of six became a small band of seven. Lucky seven. Or so they thought. After a while it became clear that was NOT the case, and his true personality shone through. His EVIL personality. And when he began to try pick them off one by one, they knew something had to be done.
They made a trap,and caught him in an ironicly funny morph: a rat. Or so they thought . . .
But now David has returned, seomthing they never thought they'd see. At the worst possible time. Because now not only do they have the newly appointed Visser One, who knows the secret of the Hork-Bajir, but David is back . . . And they know how hard it is to stop a morph-capable human- especially one bent on revenge.