Mysterious holes in the ground appear during the night, causing Oliver's bicycle to be destroyed. Who made these holes and why? The child detectives Tiril and Oliver will have to be as smart as Sherlock Holmes to find out.
1988
2007
1933
2019
1947
1949
2021
2015
1994
1983
1986
1932
1990
1965
1980
1976
1977
