Hawaii Five-0 viewers may have noticed the absence of an integral character recently, and although Steve McGarrett has enlisted Lou Grover as his opponent for verbal sparing matches, the SWAT Captain could never replace Danno.

Luckily for fans, Detective Williams (Scott Caan) will find himself back on the island for the Jan. 31 episode, "Nā hala a ka makua (Sins of the Father)." When an escaped prisoner endeavors to clear his name, he will need to take advantage of Five-0's investigative prowess. Unfortunately for McGarrett (Alex O'Loughlin) and Danny, the desperate convict will kidnap them to do so.

Teased as a" really fun and suspenseful" by executive producer Peter M. Lenkov, according to TV Line, the episode will give fans a glimpse of the partners' amusing 'bromance.'

'Hawaii Five-0' Season 4 Spoilers: Fans Can Vote On More Elements For Upcoming Episode, Chin Ho Kelly Acquires Romantic Admirer [VIDEO]

Despite the danger the duo is in during "Sins of the Father," it sounds like things will get even worse as season 4 progresses.

"Danny and McGarrett are in a perilous situation where they have to really rely on each other, and that's a real 'blood brother' type of episode," Lenkov told TV Line of episode 19.

Viewers will also be seeing more of Graces' (Teilor Grubbs) storyline and, as Danny's daughter grows older, the problems Danny has to deal with become more serious. Expect the youngster to get in trouble for punching a classmate during "Sins of the Father."

Hawaii Five-O airs Fridays at 9 p.m. ET on CBS. Click the video below to hear Danno and Steve's signature banter.