Marvin enlists the help of his twin sister Sarah and Ernie, the biggest boy in the fourth grade, to solve a mystery involving a ghostly figure and the polluting of his favorite stream.
- ISBN10 0688138861
- ISBN13 9780688138868
- Publish Date 19 May 1995
- Publish Status Active
- Publish Country US
- Imprint HarperCollins Publishers
- Format Hardcover
- Pages 145
- Language English