Normal sudoku rules apply. Adjacent digits on the red line must differ by at least 5. On land, "hotter" cells contain higher digits; i.e. orange cells contain larger digits than orthogonally adjacent yellow cells, which contain larger digits than orthogonally adjacent green cells. The four cages must be filled with four important numbers from Russ Cook's journey, read left to right. The solver must decide which number goes in which cage: 352 (days on mission); 19 (million steps, at least); 16 (countries/cells passed through); ? (total no. of "1s and 2s" on the red line)