The program's audience callers used their telephones to guide the titular character, a sympathetic small "TV troll" named Hugo, in various simple video-game scenarios to help him brave various dangers.

Typically, the goal of the game was to reach and overcome an evil witch and thus rescue Hugo's family, after which the players would be rewarded based on their performance.

[13] Target age was alternatively presented as 2-12[14] and varied depending on the country in licensed content, such as 6–16 in Portugal[15] and 6–14 in Vietnam,[16] with some family (group play) or even adult editions.

For the next season, the show was vastly expanded for new adventures at the request from Nordisk Film asking for more characters,[27] adding Hugo's 215-year-old beloved wife Hugolina (Hugoline) and their three kids: Rit (TrolleRit), Rat (TrolleRat), and Rut (TrolleRut, Ruth in some countries), who were aged between 20 (toddler) and 50 (little child).

Also added was Hugo's archenemy, the beautiful but hateful and cruel ancient witch that would become internationally best known as Scylla but originally was named Afskylia in Denmark (with several alternative names in foreign-language editions, such as Hexana in German, Maldicia in Spanish, Maldiva in Portuguese, Mordana in Croatian, Bosnian and Slovenian, Skylla in Swedish, Tarastella in Finnish, Cadı Sila in Turkish, and Simla in Vietnamese).

The terrible menace of the realm of Trollwood (in which she had been trapped by a wizard long ago[28]) and beyond, she constantly kept kidnapping Hugo's family for him to try to rescue them and defeat her.

[8][29] The subsequent editions gradually expanded on this concept to involve more characters of good (Hugo's friends) and evil (Scylla's minions) talking and humanoid or regular animals.

The game over state could be further triggered by running out of time (usually represented by either some sort of a deadly peril constantly chasing Hugo, such as an avalanche or a flood, or by his remaining amount of fuel or oxygen) or by entering an incorrect password-like puzzle sequence at the end of some levels (the latter required the players to first discover and memorize the solution, presented in the form of a particular set of three symbols randomised for each session, and then to enter it correctly).

While advancing towards one of the witch's hideouts, the players were given an opportunity to collect the scattered treasure (initially mostly bars and bags of gold) to increase their game scores.

Losing any of the lives would also play a relevant cutscene showing Hugo dying or being otherwise stopped in a cartoonish way, often uttering a sarcastic line to comment on this.

[34] A potential large bonus awaited those who successfully reached the end of the given scenario(s), during the iconic final scene in which Hugo had arrived at his destination and now stood face-to-face with Scylla.

Depending on which rope was pulled, either Hugo managed to both liberate his family and decisively defeat Scylla (who would be magically tied up and gotten rid of with the help of a spring launcher device in the game-winning best outcome), or she would still triumph in the end after all (capturing Hugo and disposing of him in the same way in an alternative game over losing state), or the family would be freed but with Scylla getting away (turning herself into a bird to escape safely in the canonical happy end); some versions would also have the witch lose her youth and beauty and become a hideous old hunchback.

The various ways leading there were not only full of traps, too, but now also populated by pirates loyal to the witch and infested with stupid and mean monkeys that she sends after Hugo.

It featured all-different main scenarios and end scenes, with diamonds replacing gold as score items, as well as introducing several new major characters such as Scylla's devoted chief henchman Don Croco and Hugo's local talking-animal helpers and guides Fernando and Jean Paul.

[38] Hugo was created by animator Niels Krogh Mortensen after ITE founder Ivan Sølvason commissioned him to design a new game produced by Pekka Kossila[39] for Eleva2ren to replace their earlier OsWALD.

Their mother, Winnie Engell, was the original voice of the antagonist Scylla,[42] whose visual design was modeled after Hugo producer Sølvason's aunt Vivi Feltman.

It was able to convert any push-button telephone's dual-tone multi-frequency signaling (DTMF) into control commands for the characters in the game,[26] allowing the callers to remotely interact with the action on TV from their homes during the live broadcast.

[47] The new system was invented by Bjarne Sølvason (father of Ivan) and could transfer an actor's body, head, eye movements, and facial expressions to Hugo's character on screen.

In Bosnia and Herzegovina, Hugo was aired from 1995 to 2004 on the country's public federal channel where it was hosted by Emela Burdžović, Mario Drmać and Elvir Hadžijamaković.

[77][78][79][80] The program was directed by Herbert Richards and hosted by Mateus Petinatti and Vanessa Vholker, who were later replaced by Andréa Pujol and Rodrigo Brassoloto.

[87] Winners of the daily editions would meet in a weekend grand finale,[88] and the journalist van called Hugomovil ('Hugomobile') traveled around Santiago to interview the program's participants.

[78] The show was initially hosted by Ivette Vergara until her pregnancy and then by Andrea Molina,[89][90] with Sandro Larenas voicing Hugo[91] and the opening theme song performed by Willy Sabor (Guillermo Andrés González Bravo).

[61] In Colombia, Hugo had his space between February 1999 and January 2001 as part of Franja Metro, the children's programming block of the Bogotá's local TV station Canal Capital.

[95] The program was presented by Boris Mirković, Ivana Plechinger and Kristijan Ugrina,[56] with Hugo voiced by Ivo Rogulja and Scylla by Đurđa Ivezić.

[78][131] The show inspired a three-hour spin-off, Hugo's World (עולמו של הוגו), in 1996,[132] in which children used a large step-on number pad to enter character movements.

[31] The content was originally modeled after the German version of the show,[134] and later developed in cooperation with the company Cenega publishing the localized Hugo video games in Poland.

[144][145] Позвоните Кузе ("Call Kuzya") was the first interactive program in the history of Russian television,[146] hosted on RTR-2 by Inna Gomes and Andrei Fedorov.

[78] In Spain, a quarter of the TV watchers tuned in to watch Hugo as part of the program Telecupón on Telecinco, a viewing figure that would remain unsurpassed since 1994.

Hugo became Turkey's highest ranking children's show and achieved a 12% share of the total market at the time when the country was new to private TV channels.

Various video games, including a series directly adapted from the 1990s show, and other media and licensed merchandise have been produced in Denmark to be distributed around the world.