While taking a walk in the countryside, Tintin comes across a plane with no registration number making an emergency landing. When he approaches the plane, the pilots shoot him and take off. As Tintin is hospitalized, he learns that an unregistered plane has crash landed in Sussex, England, which prompts him to leave the hospital and go on an investigation.
On the way to Sussex, Tintin is framed for assault and robbery by the villainous Puschov, which means that while he investigates the crash landing, he has (for the third and final time
in the series) to evade Thomson and Thompson, who are intent on arresting him. Tintin eventually discovers that he has stumbled onto a delivery system used by a gang of money counterfeiters with a hidden base of operations on the titular Black Island.
- Big Bad Duumvirate: Puschov and Dr. Müller.
- Brandishment Bluff: The exchange is:
Tintin: Hands up! (Two Mooks Tintin is standing behind put their hands up.) Put your guns down on the ground. And don't turn around, or I'll shoot... Come on, I said put your guns down!
(Mook 1 puts a gun on the ground.)
Mook 2: I... I...haven't got one.
(Snowy picks up the gun and walks toward Tintin.)
Tintin: Don't try turning round! Make just one move, either of you, and it'll be the last thing you do! (Tintin slips and falls.) Oh!
(The two Mooks turn around.)
Mook 1: Tintin! (The Mooks run toward him.) And he wasn't even armed!
- Breakout Villain: Dr. Müller is just one member of the gang of counterfeiters, though he probably has the most screentime. Despite this he is the only one to return in future stories and is even the Big Bad in Land of Black Gold.
- Counterfeit Cash
- Falling into the Cockpit: Thomson and Thompson mistakingly order an untrained engineer to fly a plane for them, resulting in them being stuck performing various accidental flying stunts without being able to land, much to their horror.
- ...and blundering into an aerial display competition. And winning it.
- Haunted Castle: The inhabitants of Kiltoch think the castle on the Black Island is this.
- Heel-Face Turn: Ranko the gorilla torwards the end.
- Hypocritical Humour: At one point, Snowy remarks how silly it is for the gorilla to be scared of a little dog, only to run away in terror from a spider the next panel.
- The old man in the Scottish pub warns Tintin off the Black Island, but when the papers are interviewing him at the end, he makes it sound as though Tintin was faint-hearted and he was the one who encouraged him to go.
- Inspector Javert: Thomson and Thompson. You'd really think they'd have caught on by now...
- Just Plane Wrong: The airplane Thomson and Thompson's commandeer stays in the air for two days. That's a pretty big fuel tank...
- Probably due to Rule of Funny
- There was a plane that stayed in the air for nine days... and yes, it was nearly all fuel tank.
- Killer Gorilla: Ranko.
- Padding: Two pages are spent watching a group of firefighters trying to find the keys to their fire station, chasing a bird who steals it, discovering that it's actually the wrong key and finally getting it from one of their wives.
- YMMV; this can be seen as an appropriate Shout Out to English farce theatre.
- Right-Hand Attack Dog: Puschov has a Right Hand Attack Gorilla named Ranko.
- Rake Take: Happens to Tintin himself, but actually works to his advantage: As he is Müller's chauffeur Ivan with a gun, he steps on a rake, but as he is hit by it, he accidentally fires and shoots Ivan's hat off, scaring him into submission. Then when Ivan realizes that Tintin has been knocked out and approaches him, Tintin wakes up and uses the rake to knock him out.
- Running Gag: Snowy gets drunk a lot in this story.
- The Sixties: An odd example; the story was originally written for Le Petit Vingtième in the late 1930s but when the English translation was colourised in 1966 it was also modernised - hence the cars and trains all come from the 60's and why Tintin is not at all surprised to see a TV. The two stories surrounding it are clearly still set in the 30's meaning that The Black Island can come across as jarring to a reader going through the stories in chronological order. It also means that Dr. Müller (originally A Nazi by Any Other Name) can come across as Eastern Bloc agent instead.
- Wounded Gazelle Gambit: Puschov does this in order to incriminate Tintin.