What happened aboard the Maginot spaceship that caused it to crash on Earth with its dangerous alien cargo? That question has haunted this thrilling spinoff of the Alien franchise from the first episode, and in a riveting flashback that plays like a self-contained Alien movie, we witness the cataclysmic chain of events that wiped out the entire crew save for the cyborg security chief Morrow (Babou Ceesay), whose mantra is, “Nothing matters but the cargo.” And what creepy cargo it is, too.

In the two-hour season finale, the final three couples engage in the “ultimate relationship test,” as the beachgoers firm up their relationships and tackle their most physically demanding challenge to date. With host Jesse Palmer guiding them toward the final rose ceremony, trust and maybe even love come into play, with $500,000 at stake.

The custody battle takes even darker turns in the penultimate episode of the gripping switched-at-birth domestic drama. Pete (James Norton), whose attempts to do the right thing keep backfiring, faces police scrutiny and suspicion, amplified by the tabloid press, that he might have switched the baby boys on purpose. The hospital is fighting back, and there’s no depths to which their malevolent adversary Miles (James McArdle) won’t stoop to keep control of both young lads, forcing Pete to take action and look into Miles’ cloudy past in Scotland. “Don’t try and be the alpha here, Pete,” Miles sneers. “It’s embarrassing.” Something tells me it’s going to be their female mates, Pete’s fierce partner Maddie (Niamh Algar) and Miles’ cowed wife Lucy (Jessica Brown Findlay), who will be the catalysts as their case heads to court.

Forget Big Brother always watching. Imagine if your soulmate had installed a secret camera in the house to record private activity, including in the bathroom. That’s the nightmare that unravels for Stacey Rutherford, a formerly single mom who built a charmed family life with Dr. Justin Rutherford in Pennsylvania until she discovered his dark secret, which included sexual child abuse as well as an unthinkable invasion of privacy. The case is told over three episodes in the true-crime docuseries based on a hit podcast, taking yet another bizarre turn when Justin is accused of plotting murder from behind bars to target a key witness.

INSIDE TUESDAY TV:

• America’s Got Talent (8/7c, NBC): Among the acts scheduled to return for the third round of quarterfinals: singer Jessica Sanchez, who earned Sofia Vergara‘s Golden Buzzer, and the juggling Messoudi Brothers, who earned Mel B’s Golden Buzzer, plus mentalist Mastermind, aerial act Jacqueline & Wagner, improv rapper Chris Turner, crossbow specialist Anna Saranina and more.
• Bobby’s Triple Threat (8/7c, Food Network): New York chef Ayesha Nurdjaja joins Michael Voltaggio and Brooke Williamson for the cooking competition’s fourth season as the trio of culinary titans who face elite challengers each week. Chef Nini Nguyen is the guest in the opener, going head-to-head in three rounds with surprise ingredients. Guest judge Daniel Boulud helps decide who wins $25,000.
• TMZ Presents: The War Over OnlyFans (9/8c, Fox): A debate over the pros and cons of the controversial OnlyFans app features interviews with model Amber Rose, porn star Angela “Blac Chyna” White, Wizards of Waverly Place alum Dan Benson and an OnlyFans creator who was a former college chancellor.
• Songs & Stories With Kelly Clarkson (10/9c, NBC): Teddy Swims joins Kelly to discuss his career and collaborate on duets of his hit songs.
• Return to Paradise (streaming on BritBox): A light-mystery spinoff of Death in Paradise stars Anna Samson as Australian expat Mackenzie Clark, whose career with London’s police force takes a detour when she reluctantly returns to her hometown Down Under in scenic Dolphin Cove. Circumstances and a murder compel her to work with the local police, including her ex-fiancé Glenn (Tai Hara), a forensic pathologist, whose mother (Catherine McClements) becomes Mack’s boss.