While it has focused primarily on female relationships from the eyes of Elizabeth Zott, Lessons In Chemistry Season 1 Episode 7, "Book Of Calvin" changes things up.

Focusing on Calvin Evans in a close-up, intimate way, we finally learn the backstory of Madeline's father, the tale Elizabeth has yearned to know for years.

Though we've heard from Calvin Evans occasionally since his untimely death on Lessons In Chemistry Season 1 Episode 2, he's been sparse.

Called in hallucinations and flashbacks, the series has allowed Calvin to take a backseat but finally answered nearly all the lingering questions the viewers and the Zott family had about him.

We learn about Calvin's troubling past, his introduction to chemistry, and the depth of his feelings about Elizabeth in one of the most interesting ways possible.

Reverend Wakely, who we learn is named Curtis, ties into Calvin's past and present, handing us a missing piece to the puzzle we weren't aware of before.

Calvin's early life is difficult, even more than he shared with Elizabeth earlier in Lessons In Chemistry.

Living at St. Luke's Boys Home in Modesto, Calvin is a bright student who uses his scientific-oriented brain to help run a candlemaking business from the basement, sanctioned by the Father presiding over the home.

Clearly against the morals of the home, Calvin isn't well-rewarded for being the brains of the operation, though he does get praise for his knowledge.

While some other boys are being adopted out, Calvin's hopes to leave St. Luke's are squashed behind his back, presumably by the higher-ups.

In his adulthood, we meet Calvin again during his first days at Hastings Lab.

He's particular about his workspace and critical of the lab's other chemists, but for good reason.

After receiving confirmation that things will be up to his standard when he returns, Lewis Pullman's Calvin heads to Boston to lecture at Harvard.

He speaks to a room of male chemistry students, including Curtis Wakely, who takes the opportunity to send him a letter about his lecture.

Curtis is frank with Calvin, asking questions and meditating on the relationship between faith and science.

While Calvin isn't religious and tells Curtis so, he explains that he's open to questions, as there are things science can't even explain.

The men correspond back and forth, going from broad topics like chemistry to specifics, like their personal lives.

Forging a cross-country bond, Curtis and Calvin get to know one another on a personal level as Calvin gets settled in his new lab.

When he meets Elizabeth, Curtis is among the first to know about it.

Calvin, who's been abandoned by his family in more ways than one, finally feels like he has people to turn to.

Calvin meets Aja Naomi King's Harriet Sloane and her husband, Charlie, when they come over to welcome him to their neighborhood.

He's built a unit around himself, and watching him flourish in having people who care for him is fascinating.

Calvin acquires such depth throughout Lessons In Chemistry Season 1 Episode 7, depth we, as viewers, knew was there but didn't have enough time with.

Elizabeth, who enters the episode after meeting Calvin in moments we've seen and moments we haven't, shares the same sentiment.

She didn't have enough time with Calvin to know who he was at the deepest points – but as viewers, we're afforded the luxury of seeing him more clearly.

The moments between Calvin and Elizabeth throughout the episode highlight their relationship from Calvin's perspective.

Understanding Elizabeth was never difficult for him, and in his letters to Curtis, Calvin shares that he's never been so in love with someone before.

Calvin's open about wanting to marry Elizabeth, even asking for Curtis' advice on a potential proposal.

Ultimately, though he's already purchased a ring, Calvin respects Elizabeth's wishes and loves her more for being upfront with him.

In the small moments, we see how Calvin adored Brie Larson's Elizabeth despite her quirks and character flaws.

As we get closer to the tragedy of Calvin's death, it's clear he's in the best place he's ever been.

After writing Curtis a letter about Elizabeth and how things have been, Calvin sends it off before taking Six-Thirty on one last fateful run.

Curtis' reply, which is returned to sender after it's sent to Calvin at Hastings posthumously, mentions he'll be moving back to California.

Unfortunately, Curtis isn't aware of the tragedy until long after it happens.

One loose thread is woven throughout the episode, as Calvin's involvement with the Remsen Foundation remains unexplored.

Wilson Remsen, played by Beau Bridges, makes a few short appearances throughout the episode.

First, we see him at St. Luke's, potentially inquiring about Calvin before being rebuffed. Later, we see him again in his office, waving off his secretary.

While Remsen himself may not be much of a mystery, we have yet to unpack a layer of involvement with Remsen, Calvin, and how he became so prolific.

After finally meeting Curtis, who brings his letters from Calvin for them to read, Elizabeth and Madeline head to Modesto to visit St. Luke's and ask if there's anything of Calvin's left there.

Reverend Curtis Wakely immediately understands Calvin and Elizabeth's connection, happy to meet her and know that she loved him like Calvin did.

His advice to Mad about researching the various St. Luke's homes was helpful, but the meeting itself is complex.

Though much older, the original Father who wouldn't allow Calvin's adoption out explains to Madeline and Elizabeth that there's no record of him being at home.

Madeline, angry, tries to reason with the Father, but he won't budge. He explains that Calvin's records were likely destroyed in a fire, though it's a lie.

After going to the library, Madeline pulls books off the shelves to see if Calvin checked any of them out.

Elizabeth does her best to discourage her from a thankless task, but Mad is too determined and sits down on the ground to help.

Quickly, they discover Calvin's name scrawled across a checkout card in a copy of Great Expectations.

Elizabeth notes that the Remsen Foundation donated the book.

While Lessons In Chemistry Season 1 is coming to a close, there's still one more mystery for Elizabeth Zott to solve.

Cher Thompson is a staff writer for TV Fanatic. Follow her on X.