A very old clue is about to get a breath of new life on Hawaii Five-0.

The hunt for Wo Fat (Mark Dacascos) has taken a backseat to Danno's (Scott Caan) familial issues, but John McGarrett's old toolbox may still hold one more secret.

Steve McGarrett (Alex O'Loughlin ) and Detective Williams will have their hands full when a father is shot and his daughter is kidnapped during "Ma lalo o ka 'ili (Beneath the Surface)," but Jerry (Jorge Garcia) will be working on an entirely different case. The conspiracy nut may drive McGarrett slightly insane, but his keen eye and knack for puzzles will enable him to decipher a code at the bottom of the elder McGarrett's old toolbox.

That's right, the rusty and chipped Champ box is back in play. After making its debut during the series premiere back in 2010, the dilapidated toolbox has been McGarrett's only link to his father's Wo Fat investigation over the last four years. While is has not been explicitly stated that the clue will relate to Wo Fat, its location and cryptic nature smack of a return to the Wo Fat chase.

Hawaii Five-0 airs Fridays at 9 p.m. ET on CBS. Scroll through the gallery above to see what's in store for the Five-0team during "Ma lalo o ka 'ili," and click the video below for a quick preview.

Tags
Hawaii Five-O, CBS, Television