The answer may surprise you: maybe. Sherlock Holmes and Doctor Watson have long been in the public domain, but legal battles over the iconic duo’s copyright continue. Last year, Sir Conan Doyle’s Estate filed yet another infringement lawsuit, this time against Netflix and other creators of the film Enola Holmes. The lawsuit was settled, but the case’s main question still remained: can anyone use Holmes and Watson, or not quite yet?
The answer seems simple: the characters are in the public domain, and therefore anyone is free to use them. But, according to the Estate, there are multiple versions of Holmes. He allegedly developed certain character traits later in life, and accordingly, in later stories. This is important because a few late stories featuring Holmes are still protected under U.S. copyright law. According to the Estate’s complaint, Netflix and other defendants borrowed Holmes from those still-protected stories.
This seemingly bizarre theory is actually grounded in copyright jurisprudence, and offers us a glimpse into the next decades of copyright litigation, when our childhood heroes and heroines will start entering public domain one story at a time.
Why are things so complicated?
The UK copyright in Holmes and Watson expired in 2000—70 years after Sir Conan Doyle’s death. But U.S. copyright law is anything but a set of bright-line rules. The duration of the U.S. copyright depends on many factors, including when the work was created, when and whether it was published, whether the copyright was renewed, etc. To make things even more complicated, under certain circumstances, foreign works can even be retrieved from the public domain.
Since 2002, U.S. copyright in literary works—if they were not made for hire—also lasts 70 years after the author’s death. However, Sir Conan Doyle wrote the Holmes stories between 1887 and 1927, long before the U.S. copyright became that straightforward. This is why the stories have been entering the public domain one by one, creating a unique opportunity to squeeze out extra licensing fees.
The copyright does not protect ideas themselves, but rather their expression. Yet, expression goes beyond exact words or images: story elements, such as plot or characters, are copyrightable if they are defined in sufficient detail. Unlike the plain text of a novel, characters may evolve over series of works. The paradigmatic example is Superman. His first version will enter public domain in 2033 but without his signature superpower—the power of flight. Similarly, a “gun-wielding murderer” Batman, who will enter public domain in 2034, might not closely resemble the modern “no kill” version of himself.
This is the essence of the Estate’s claim: Sherlock Holmes in the later stories is not the same as his 1887 counterpart. So, what’s the difference? According to the Estate, after World War I, Sir Conan Doyle was confronted with the deaths of his loved ones. This caused Doyle to rethink Holmes’s character and transform him from “a brain without heart” into “a character with heart.” More precisely, Holmes developed the following traits: genuine friendship with Watson, reacting to women with warmth and emotion, great interest in dogs, and embracing new technologies.
Where did this argument even come from?
Up until 2014, the business was good. Despite seemingly expired copyright, the Estate required a $5,000 license fee from authors who wanted to use Holmes and Watson. Those who refused to pay faced the prospect of being banned from large retailers like Amazon and Barnes & Noble. In 2013, a publisher, intimidated by the Estate’s demands to pay the fee, backed out of its deal with writer Leslie Klinger. In response, Klinger sued the Estate for a declaratory judgment stating that he was free to use anything from Sir Conan Doyle’s public domain works, including the characters.
In response, the Estate advanced a novel claim: because Sir Conan Doyle developed Holmes and Watson throughout the series of works, the characters should remain protected until the last story featuring them enters public domain. The Seventh Circuit, however, found that the Holmes and Watson from the last few novels were merely derivatives of the original characters. Therefore, only “incremental additions of originality” to the characters were protected, but not the characters themselves.
In its decision, the court relied on the Second Circuit case Silverman v. CBS Inc. In Silverman, Stephen M. Silverman wrote a script for a Broadway musical based on the “Amos ‘n’ Andy” characters. CBS arguably owned copyright for post-1948 “Amos ‘n’ Andy Show” radio programs but lost its copyright for the pre-1948 programs. Silverman sued CBS for a declaratory judgment that the programs were in public domain, and he was free to use their material, including characters and plot.  CBS countersued for, among other things, copyright infringement. The court held that Silverman was free to use any elements of the pre-1948 programs but was enjoined from using “any further delineation of the characters” added in the post-1948 works. Similarly, the Seventh Circuit in Klinger found Holmes and Watson to be in public domain save for features added in the still-copyrighted works, provided those features were original.
Despite the warnings that the Estate’s copyright had largely expired, the decision left an open door to claim that a particular version of Holmes exhibits traits from the still-protected works. The chance presented itself in May 2015, when the Estate sued Miramax over its film Mr. Holmes. The Estate alleged that Mr. Holmes’s screenwriter, Mitch Cullin, copied some of the scenes and character traits that were developed in the protected stories. Namely, Holmes started liking dogs and displaying warmth towards women. The lawsuit was ultimately settled.
In June 2020, the Estate filed the lawsuit against Netflix and other creators of Enola Holmes. The film was based on Enola Holmes Mysteries, a series of novels by Nancy Springer. The Estate alleged that Springer depicted Holmes with the above-mentioned traits developed only in still-copyrighted stories. Accordingly, the film, being a derivative work, infringed on the Estate’s copyright. In its motion to dismiss, Netflix and other defendants denied that separate traits of Holmes’s personality could be protected at all. And even if personality traits were copyrightable, the Netflix version of Holmes had only two allegedly infringing traits—display of emotions and respect to women—and both of these traits originated in the stories that had already entered the public domain. Thus, even if the parties did not settle, the court likely would have dismissed the complaint without deciding the ultimate question of personality traits’ copyrightability. The settlement left us wondering what traits are original enough to justify the copyright, and what traits are too general. Now we will have to wait for future lawsuits. Until then, anything and everything seems possible.
 Klinger v. Conan Doyle Estate, Ltd., 755 F.3d 496, 501 (7th Cir. 2014).
 First Amended Complaint at 2-11, Conan Doyle Estate Ltd. v. Springer et al, No. 1:20-cv-00610-KG-KK (D.N.M. Oct. 16, 2020).
 Klinger, 755 F.3d at 498.
 First Amended Complaint, supra note 4, at 2-11.
 See generally Peter S. Menell, et. al., Intellectual Property in New Technological Age: 2020. Volume II: Copyrights, Trademarks & State IP Protections 631-33 (2020, Clause 8 Publishing).
 Id. at 542 (citing Dam Things from Den., a/k/a Troll Co. ApS v. Russ Berrie & Co., Inc., 290 F.3d 548 (3d Cir. 2002)); see also Twin Books Corp. v. Walt Disney Co., 83 F.3d 1162 (9th Cir. 1996) (holding that Bambi’s copyright restarted when the work was republished with the U.S.-law-complaint copyright notice).
 Peter S. Menell, et. al., supra note 8, at 631.
 See generally 1 Nimmer on Copyright § 2.12 (2020).
 First Amended Complaint, supra note 4, at 7.
 Id. at 7-8.
 Klinger, 755 F.3d at 497.
 Id. at 498.
 Id. at 500-01.
 Id. at 501.
 870 F.2d 40 (2d Cir. 1989)
 Id. at 43.
 Id. at 50.
 Klinger, 755 F.3d at 502.
 Complaint at 2-4, Conan Doyle Estate Ltd. v. Miramax et al, No. 1:15-cv-00432-WPL-KBM (D.N.M. May 21, 2015).
 Id. at 4-5.
 Complaint, supra note 32, at 8-10.
 Id. at 10-11.
 Film Defendants’ Motion to Dismiss First Amended Complaint at 9, Conan Doyle Estate Ltd. v. Springer et al, No. 1:20-cv-00610-KG-KK (D.N.M. Oct. 30, 2020).
 Id. at 9-12.