A finale and a Proposal take us into summer

Here’s what’s happening in the world of television for Monday, June 18. All times are Eastern.

Top pick

Supergirl (The CW, 8 p.m.): In the season-three finale, “Battles Lost And Won,” Kara (Melissa Benoist) prepares for her final bout with Reign, who’s still hellbent on terraforming Earth to create a new Krypton (gee, where have we seen that before?). After teaming up with Mom, Supergirl might get a hand from Sam (Odette Annable), who wandered off to the Valley Of Juru in search of the power to defeat Reign once and for all. Caroline Siede will be on hand to welcome our new Kryptonian overlords, or say goodbye to Reign for good.

Wild card

The Proposal (ABC, 10:01 p.m.): Summer officially kicks off in just three days, but it sounds like ABC execs had already mentally checked out when they green-lit The Proposal, a new dating reality series from Mike Fleiss. If you ever watched The Bachelor and felt the couples who had known each other for just weeks before getting engaged could have gotten hitched more efficiently… well, even then, this show might not be for you. As Alex McLevy puts it, “It seemed there was no way ABC would be dumb enough to bring back the most appalling and cringeworthy elements of a roundly scorned TV special from nearly 20 years ago. But as it turns out, ABC is exactly that dumb.”