Warning for SPOILERS



In the first two episodes of This Is Us season 4, we see Randall's family adjusting to Philadelphia, Kevin's career taking off while he focuses on his sobriety, and Kate and Toby taking their newborn son home after learning that he's permanently blind.

But what's driven over 7 million viewers crazy is that season 4 introduces a bevy of new characters and barely a hint of how their lives connect to the Pearson family. In particular, Cassidy Sharp (played by prime time darling Jennifer Morrison, Once Upon a Time, House) is a military officer whose return home is complicated by symptoms of PTSD, struggles to find employment, and a drinking habit that grows steadily out of control. Who is she and how is her life entwined with the Pearsons?

This Is Us Season 4 Trailer (HD) youtu.be

One of the show's greatest strengths is its diverse team of writers (spanning races, genders, and body types) who have perfected a formula of curveballs and high drama twists that practically begs for out-there, elaborate fan theories. In eschewing the campy drama of soap operas, This Is Us also manages (for the most part) to avoid exploiting trauma for the sake of high stakes plotlines. Showrunner Isaac Aptaker says the production has "really, really tried to make the writers room a place where we can have those kinds of conversations—the kinds you don't have permission to have in your daily life." Combined with their time-warping twists, dry wit, and ability to script a chaotic family argument that spans from childhood slights to not being worthy of a dead father's memory, anything could happen on season 4. But we'll bet these Cassidy Sharp fan theories are onto something.

She's the Mother of Kevin's Son's

Struggling with PTSD, she's separated from her husband and has inadvertently lashed out at her son. After sharing her growing drinking problem at a VA meeting, Uncle Nicky suddenly appears by drunkenly throwing a steel chair through the window.

Season 4, Episode 3: Truth Comes Out - This Is Us (Promo) youtu.be

The season finale of season 3 revealed that perpetual bachelor Kevin ends up having a son, prompting fans to comb through every female character to appear on the show to sleuth out who the mother is. One theory postulated that Kate's best friend, Madison, bore a striking resemblance to the boy—in so far that she was blond(e) and attractive. But so is Kevin, himself. But the promos for the next episode tease Cassidy's introduction to Kevin, and odds are strong that they form a bond through Kevin's Uncle Nicky and their struggles with sobriety. Cassidy and Kevin forever?

OR Cassidy Sharp Is...a Pearson?

Days before season 4 premiered, showrunners took to Instagram to call for fan theories. For some reason, one popular one is that Cassidy Sharp, rather than being a love interest for Kevin, is his long lost relative, namely his cousin or even his sister. While fans have readily placed Jack Pearson on a pedestal in TV's hall of fame of greatest dads, part of the show's appeal is its realistic depictions of people's flaws, from perfect Randall's mental breakdown to Rebecca Pearson admitting that she plays favorites with Randall.

So, the theory goes, maybe Jack had a child out of wedlock before he met his soulmate, Rebecca? Or, maybe he even had an affair? There's not much evidence to support this theory other than the fact that Cassidy is a strong soldier who struggles to discuss what she saw on duty when she returns home, which is similar to Jack after Vietnam. But another iteration of this theory is that she's actually the estranged daughter of Kevin's Uncle Nicky, which, sure, is perfectly plausible since we know next to nothing about Nicky's life. We have yet to see Cassidy or Nicky interact beyond Cassidy's long, shocked look out the broken window Nicky's just smashed.

Maybe it's Jennifer Morrison's stoic face or her impeccably plucked eyebrows, but we're dying to know who Cassidy Sharp is. You can find plenty more theories on the This Is Us Instagram. Let us know if you're onto something.