A Puck Line bet is the hockey version of a spread. A number of goals is added to or subtracted from your selection's final score, and your bet wins if your selection is ahead after the adjustment. Overtime and shootout goals are included.
For example: the Stars are -1.5 against the Maple Leafs. If the Stars win 4-2, they cover. If the Stars win 3-2 in overtime, or win a shootout (which counts as a 1-goal win), they don't cover, and a bet on the Maple Leafs +1.5 wins.