A professional artist and sculptor, Tessa is the lover and confidant of the series protagonist Duncan MacLeod, played by Adrian Paul, an immortal swordsman born centuries before in the Scottish Highlands.

In the pilot episode "The Gathering," Tessa is said to have been in a relationship with Duncan for twelve years already and the two co-own MacLeod and Noël Antiques in the fictional city Seacouver, Washington.

[1] When she is seven years old, she falls in love for the first time with then-nineteen-year-old Alan Rothwood (Anthony Head) and is "heart-broken" when he completes his studies and leaves the country.

[4] Skilled at illustration[5] and sculpture (using either metal[6] or modelling clay[7]), Tessa begins working as an artist while also having a day job as a tour guide for the River Seine in Paris.

On April 1, 1980, while escaping an enemy, the immortal Duncan MacLeod leaps off a bridge and lands on a Bateau Mouche boat where Tessa is conducting a tour.

After Slan flees to continue the battle another time, Duncan explains that Connor is from his clan and also immortal, born almost 90 years earlier.

During this time, the two of them meet 17-year-old petty thief Richie Ryan (Stan Kirsch), who learns from witnessing the MacLeods fight and behead Quince that they are immortals.

Wanting to watch over the young man and believing he is not an inherent criminal but simply someone who needs guidance, Duncan and Tessa hire Richie to work in their shop, forging a friendship.

When Tessa witnesses the brutal murder of former artist Anne Wheeler, she becomes enraged when the police seem unwilling to do something and decides to investigate on her own.

Soon afterward, Duncan meets the Watcher Joe Dawson who explains the rest of his organization is benevolent and sworn to not interfere with the lives of immortals or their loved ones.

On their way to the car, Tessa and Richie are mugged and shot dead by Marc Roszca, a drug addict wanting their money.

He is forced to confront his guilt and grief regarding Tessa when he meets a woman sharing her appearance in the second season two-part finale "Counterfeit."

[18] Executive producer William Panzer was intrigued by the idea that a mortal would want to spend their life with an immortal despite the drawbacks and possible dangers.

[19] Panzer said creating interesting female characters in the Highlander franchise was often a challenge because the producers found it difficult to "have the women be something other than a victim, a hostage, other things when dealing with an immortal hero.

"[20] In the script of "The Gathering," Tessa is described as "a beautiful, elegantly casual woman, artist, free spirit, and proprietor of the most unusual antique shop in the city.

"[23] Producer Barry Rosen said, "We were very lucky that [Vandernoot and Kirsch] were so human-grounded, so we could really play off of them and the way they looked at things that [Duncan MacLeod] went through.

"[26] In the show, Tessa is in her mid 30s while Richie is just shy of his 18th birthday when they meet, leading to a relationship not unlike an older sister and younger brother.

David Abramowitz, creative consultant starting in the second season and later an executive producer on the show, said, "When I saw her and Adrian together, I thought that if I died, and there was a Mount Olympus, that the two of them would be standing together with thunderbolts around them.

"[29] Reviewer Abbie Bernstein of the Audio Video Revolution website wrote that Tessa was "depicted not as a screechy, in-the-dark Lois Lane but rather as a woman who handles her lover's supernatural aspects with remarkable pragmatism.

"[30] Berstein added Tessa was "an unusually gutsy love interest (not to mention a refreshing sexually active heroine, as opposed to the coy 'sexual tension'-generating females who usually populate the genre).

"[32] Reviewer Doug Anderson of The Sydney Morning Herald wrote that Tessa was "too arty and sympathetic to serve any purpose other than an emotional spur for the hero's vengeance."

Joanne Ostrow of The Denver Post wrote that "Paul and Vandernoot don't look like typical American TV-style bimbos and hunks, and for good reason.

[24] According to Abramowitz, another reason was that "[Vandernoot] being a really strong actress wanted to play a more aggressive part in the show and sadly, the nature of the beast was that it couldn't happen [with Tessa] and she made a decision.

To surprise audiences and not make the death seem formulaic, the creative staff decided Tessa would die in a random mugging incident rather than be murdered by an enemy of MacLeod's or as part of the episode's main storyline.

Horvath said "losing a loved one to a random act of violence is something that happens totally unexpectedly, at a moment that makes no sense dramatically".

[36] During the filming of the episode, no dialog was recorded and the final broadcast version shown in North America did not show Richie revive.

Highlander is a fantasy series, yet I cared about the characters as though I know them... Vandernoot gave Tessa such vitality and charm that her death left me reeling.

"[38] Tessa remained extremely popular with the audience after her death, prompting the producers to develop the season two finale episode "Counterfeit" to bring her back in some way, at least temporarily.

[42] In the two-part finale to series two, "Counterfeit" (1994), Vandernoot returned as the character Lisa Halle, a woman who undergoes plastic surgery and vocal training so she can resemble Tessa in voice and appearance.

Pretending to be Lisa Millon, a French artist with a striking resemblance to Tessa, she lures MacLeod into a false sense of security so his enemies can attack him when he's vulnerable.