When Marco and the other Animorphs investigate Visser One's secret underwater project, Marco finds out that his mother is his worst enemy -- the leader of the Yeerk invasion of Earth.
- ISBN10 0590255436
- ISBN13 9780590255431
- Publish Date 1 February 1998
- Publish Status Out of Print
- Out of Print 10 January 2012
- Publish Country US
- Imprint Scholastic US
- Format Hardcover
- Language English