The following version of this novel was used to create the guide: Wolfgang-Smith, Olivia. Glassworks. Bloomsbury Publishing, 2023.

The novel begins in the year 1910 as Agnes Carter, a wealthy Boston heiress, endeavors to use her clout with a local university to invite a glassblower from Bohemia to the area. When the glassblower in question, Ignace Novak, arrives in the city, he and Agnes immediately develop a quiet friendship in spite of open disapproval from the university board and Agnes' unnamed husband. Over time, Agnes' relationship with her husband grows increasingly strained and abusive, and Ignace slips further and further into a lethargy that he describes as "madness." When Agnes' husband endeavors to both arrange for Ignace's dismissal and commandeer Agnes' long history of contributions to the university for himself, she bitterly decides to poison her husband at the grand opening of the art installation that Ignace has worked tirelessly to install. Following her husband's murder, Agnes initiates a romantic relationship with Ignace, and the pair flee the city together.

In 1938, Edward Novak, Agnes and Ignace's son, departs from their family home in Chicago in order to apprentice with a Boston glassblower named Mr. Reid, who hires Edward because of his respect for the family name. Edward has little interest in glassblowing and wishes instead to become a priest, something he has found difficulty achieving because of his parents' atheism. Edward endures several weeks in Boston clumsily performing unfulfilling work for Mr. Reid before meeting a young woman named Charlotte Callahan, whose father is a prominent and wealthy figure in Boston that ostensibly runs a collection of factories and mills. To Edward's surprise, he finds himself in the midst of a passionate romance with Charlotte, who begins drawing Edward further and further into her family unit and reassuring him with promises that her father, Fred, will offer him work at the factory if Edward's ill-fated arrangement with Mr. Reid falls through. Thanks in part to his frustrations with his parents and his disdain for the glasswork industry, Edward abandons his work with Mr. Reid and cuts off his parents, only to discover that Charlotte has lured him into a predatory scenario; Mr. Callahan is associated with the Boston mob, and Charlotte initiated the relationship with Edward in order to secure a patsy for her father's various fronts. She entreats Edward to run away to New York with her, and, devoid of other options, Edward agrees.

By 1986, Edward has grown into old age after a long and arduous career working as a window-washer in New York City, and is cared for by his adult daughter, Novak. Novak is a lesbian woman who has also worked as a window-washer her entire life, and her only close relationships are with Edward and her best friend, Felix, an ambitious gay man trapped in an abusive relationship with his sugar daddy, Jack. One day, Felix insists on taking a disgruntled Novak to a Broadway show, and Novak becomes entranced with one of the background dancers in the performance, who is billed as Cecily Wonder. After the show, Cecily invites Novak and Felix backstage and introduces them to the star of the show, a man named Kent Casper. Following the meeting, Felix becomes more and more evasive of Novak's attention, and she finds herself obsessing over her mother, Charlotte, who abandoned her when she was young.

Some time later, Cecily summons a nervous Novak to her apartment and confides in Novak that she is angry with her best friend, Tabitha, for settling down with a man and moving out of their apartment. Novak is wounded to learn that Felix has begun dating Kent, and grows frustrated when she realizes that Cecily willingly abandoned a relationship with her parents, eventually rummaging through Cecily's purse in order to find her driver's license and discover her real name and address. Hoping to reunite Cecily with her parents, Novak summons them to New York so that they can watch Cecily's next show, but quickly realizes that this was a mistake; the parents, Helen and Don Alberico, hope to take Cecily back to Pennsylvania with them and force her to marry a man she does not love. Cecily catches sight of her parents while she is performing and loses focus, causing her to miss her mark, tear her ACL, and be carted to the nearest hospital. Desperate to make things right, Novak rushes to the hospital and manages to use her knowledge as a window-washer to clamber along the outside of the building to Cecily's window; Cecily, however, refuses to let Novak in, which causes Novak to fall to her death.

Finally, in 2015, Cecily's two daughters, Flip and Tabitha Brightman, struggle to take care of Cecily as she lapses slowly into madness. Although Tabitha has built a stable and successful life for herself, Flip's is in a decidedly disheveled state; she still lives with her ex-girlfriend Jocelyn despite their falling-out, has developed a weed dependency, and works for minimum wage at a company called Solid Memories, which turns the ashes of people's pets into small glass animal figurines. When Denise, the standoffish glassblower at Solid Memories, discovers that Flip's real name is "Novak," she speculates that Flip might be related to Agnes and Ignace Novak, who are still famous within the glassblowing community for their work; Flip becomes obsessed with the Novaks and is convinced that she has a glass honeybee in her possession that was designed by Ignace Novak. Tensions grow between Flip and Denise before it is announced that Solid Memories is going out of business; to make matters worse, Flip discovers that Tabitha and Jocelyn have been carrying on a secret friendship behind her back, and that Jocelyn intends to move out of their apartment and in with Tabitha, meaning that Flip will no longer be able to make rent. After enduring a brief arrest when she tries to enter the Solid Memories office after hours, Flip manages to locate the honeybee and patch up her relationship with a now-homeless Denise before offering Denise Jocelyn's old room.