7-year-oldBertil'sparentsareatworkandBertilarehomealoneandbored.HeistheonlychildinthefamilysincehissisterMarthadiedofanillness.ButeverythingchangeswhenhemeetslittleNilsKarlssonPysslingandtheybecomefriends.NissewholivesinthebasementinaroomherentsfromtheratTjofsan,wichiscruel.
