Normal sudoku rules apply. Draw a single 1-cell-wide loop of orthogonally connected cells into the grid that does not branch or enter any cell more than once. The loop must pass through all given dots, and all given dots must be in the middle of a straight loop segment (i.e., the distance from a dot to the next turn along the loop must be identical in both directions). Digits separated by a grey dot are consecutive or one is double the other. Adjacent digits on the loop not separated by a dot must NOT be consecutive or where one is double the other.