This is the cassette release of Misja / Fred (2nd edition with music), published in October 1991 by LK Avalon. The appropriate entry for these files at Atarimania is

http://www.atarimania.com/game-atari-400-800-xl-xe-misja-fred_1218.html

The files are:
* Misja + Fred (1991-10)(L.K. Avalon)(PL)(Side 1 of 2)[misja].cas
  CAS image of tape side 1
* Misja + Fred (1991-10)(L.K. Avalon)(PL)(Side 2 of 2)[fred].cas
  CAS image of tape side 2
* inlay-front.jpg
  Scanned exterior of the cassette inlay
* inlay-back.jpg
  Scanned interior of the cassette inlay
* cassette-side-1.jpg
  Image of the cassette sside that contains Misja
* cassette-side-2.jpg
  Image of the cassette sside that contains Fred

The CAS images are 100% original, unmodified, uncracked images of the tape contents. They are runnable on the most recent versions of Altirra and Atari800 (on the latter emulator, SIO patch must be disabled). To load either of the two games, mount one of the CAS images, then boot the computer while holding Start+Option etc. The games probably work only on XL/XE machines.

The currently-available ZIP archive at Atarimania contains cracked and/or broken CAS images of this tape. The following files should be removed from the archive:
Fred _ 1991 _ fixed loader.cas
Fred _ 1991 _ original.cas
Misja _ 1991 _ fixed loader.cas
Misja _ 1991 _ original.cas

The new CAS images are meant to replace the above four files.