Back in November, Australian viewers saw Heath left for dead out at sea after being attacked by unstable Jamie Sharpe (Hugo Johnstone-Burt) in the soap's 2012 season finale.
As the show's 2013 season kicks off, Heath's on-off love interest Bianca Scott (Lisa Gormley) is first to notice that he is missing, and she raises her concerns with Brax.
With half-brother Kyle (Nic Westaway) backing him up, Brax has a dramatic showdown with Jamie, realising that he and his villainous father Adam (Martin Lynes) must be responsible.
Peacocke told TV Week: "Bianca's genuinely worried, so [Brax] thinks, 'Okay, this is cause for concern'. He starts piecing together everything that's been happening with Jamie and Adam, and then with Heath and Jamie becoming friends.
"He goes back to his tried and true method of just bludgeoning the truth out of someone. Brax knows that time is crucial. He needs a quick answer, and he gets it."
Jamie ultimately helps Brax and Kyle to search for their brother, but when they find his dinghy out at sea, Heath himself is nowhere to be seen.
Peacocke continued: "At first, Brax fears the worst. They're in the middle of the ocean and his brother isn't there, but being an eternal optimist, Brax thinks he can find him. He'd never forgive himself if he just gave up right there."
Meanwhile, Dan Ewing - who plays Heath - warned that the Braxton siblings will want payback once the dust settles.
He said: "There will be repercussions for Jamie's actions, especially if Heath can make it back alive."
Home and Away airs these scenes next week on Network Seven in Australia, and in February on Channel 5 in the UK.
Watch Home and Away's 2013 promo in the video below:
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