This is a very good, pleasant and exciting summer mystery with all the classic ingredients — exciting situations on land and under water, modestly scary (kind) monsters, kind but slightly naive adults, and plucky children. Hans Jørgen Sandnes’s images are well drawn with clean lines and details, and are brightly coloured. The dialogue is kept short and the plot easy to follow. A wonderful adventure suitable for pre-teens and slightly younger children. Overall rating 4 out of 5.
- Per Berg, BTJ-häfte nr 16/22