A war against a killer alien invader doesn't stop Humans from being human.

The humans fight against the Espheni on Falling Skies in order to maintain what makes them uniquely human. One of those traits is love.

With lives lost every day, it would make sense for people to build a wall around themselves to protect their hearts from loss, but instead the danger and risk drive their need to have someone to love and love them.

Watch Falling Skies Season 4 Episode 9 Online

The 2nd Mass spends every day just trying to survive, but what's the point without someone to share their lives. Of course, they have each other and some of them have family members, but romantic love is something that keeps the human spirit alive and makes the fight worth it. That's one of the reasons the Espheni's human evolution plan will likely fail.

On Falling Skies Season 4 Episode 9,  we saw several couples deal with the troubles and glory of being in love. The importance of opening up to the possibility was seen through Sarah. She was alone, but safe before her path crossed Pope's. Despite the safety that she gave up and the killer she became, she wanted the companionship, love and friendship that she was building with Pope.

He pushed her away out of fear of letting someone in, but he quickly realized he made the wrong decision. The future of their relationship is doubtful since she left on a supply run. If she returns, Pope should beg her forgiveness and let her into his life for real. He needs someone just like Sarah.

Whether you like or don't care for the love triangle situation between Ben, Maggie and Hal, the three of them have a complicated relationship and the alien spikes haven't helped. It makes sense that Ben would admire Maggie and equate that to a romantic love, since he's been cheated out of a normal teenage romance. Before Maggie got his spikes, he honored his brother and never crossed the line with Maggie.

It was Maggie that kissed him. Their new biological connection and the high she was feeling from her new abilities pushed her to act out of heightened emotional feelings. She couldn't help herself any more with Ben in that moment than she could when the flung the metal at Sarah. Given Ben's reaction, there's not really a triangle at all.

When she said she never had feelings for him before the spikes, he pushed her away. He doesn't want faux love from her. I give him a lot of credit for his restraint. Whether that will hold or not is unclear. The biological alien connection may end up being more than either of them can overcome, but for now, Ben didn't deserve Hal's punch. (Though, Hal doesn't know that and his reaction was understandable.)

Love makes humans vulnerable, but it also makes them strong. Matt let his feelings for Mira get the better of him. It was clear from the moment she showed up that she was brainwashed at the Espheni youth school. Tom should have kept his son away from her, though in the end it all worked out.

The attack brought Tom and Anne together and gave them the whistle they needed for the Espheni ship. Tom's proposal was perfectly timed. Their union brought strength to both of them, the Mason family, and even the 2nd Mass. It provided an infusion of hope that reminds them all of their humanity and will help them all get through the next fight.

"We choose to go to the moon." That's quite a wedding present!

How crazy is the plan to go to the moon?

Carla Day is a staff writer for TV Fanatic. Follow her on Twitter and on Google+.