It's hard to fathom how a 12-metre-long painting could go missing.

But that's what happened about two decades ago to The Demise of Seventeenth Avenue — the 13-panel artwork Robert McInnis crafted between 1979 and 1982 in Calgary.

During that time, he painted 60 portraits of the movers and shakers in the city's art scene who congregated along 17th Avenue S.W.

Artists like Illingworth Kerr and Joane Cardinal Schubert, curator Nancy Tousley and art dealer Douglas MacLean.

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In 1982, the artist lent the work to a friend who had the wall space to hang the huge painting in their Calgary home. (Glenbow Museum)

The Glenbow Museum described the work as "epic."

"Just as Calgary was experiencing a boom at the time, our art scene was really experiencing unprecedented growth," said museum spokesperson, Zoltan Varadi.

"So it was a really interesting historical document of some of the people who were working in the art scene."

'We would be the custodians'

According to the Glenbow, McInnis didn't have the wall space to hang the massive painting — so he lent it to a friend in 1982. 

That friend was Tim Christison, who left the paintings on the wall of her Bankview home when she rented it to Kathy Bentley and her husband in 1987.

They eventually bought the home from Christison under the condition that they would take care of the paintings and eventually, return them to the artist.  

"We would be the custodians," said Bentley.

Journey to Yellowknife

In 1992, Bentley tried finding McInnis before she and her family moved to Yellowknife — but the phone number she had for him was disconnected.

"This was all pre-internet days so there wasn't such a thing as Googling it to find him," said Bentley.

'I loved the paintings — the people in them. I felt they were part of my life. They were my inanimate, inarticulate, non-verbal friends.' - Kathy Bentley

She also couldn't reach Christison, who was fighting terminal cancer when she sold Bentley her home five years earlier.  

Bentley feared Christison had passed away (she in fact, hadn't and is still alive), so she crated the paintings up and took them north. 

"We weren't going to leave them in Calgary. And we loved the paintings. They're very special."

And for the next 22 years, they hung in her Yellowknife home.

Reunited in Calgary

Through the magic of Google, in 2014 Bentley's daughter helped connect her with the artist through his website and gallery in Winnipeg, where he currently resides.

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"The Demise of Seventeenth Avenue" was painted by Robert McInnis between 1979 and 1982. (Glenbow Museum)

To be cautious, she had her lawyer reach out to McInnis.

"I didn't know whether or not Robert would be upset or happy or would think that I had stolen the paintings," said Bentley.

Her lawyer got a message from McInnis "within hours" of reaching out. 

"Everything since then has been just the development of a very wonderful friendship."

New home at Glenbow Museum 

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In 2014, Bentley connected with McInnis and they agreed that the work should be in a public collection. (Glenbow Museum)

Bentley and McInnis met, and agreed, that the entire series should be in a public collection in the city it was created.

The paintings are now part of the permanent collection of the Glenbow Museum.

"Important historically as well as artistically, the painting documents a pivotal time in the development of Calgary's art scene, and records many of the individuals involved in building our city's art community," the museum said in a release Thursday. 

"It's very bittersweet, I loved the paintings — the people in them. I felt they were part of my life. They were my inanimate, inarticulate, non-verbal friends," said Bentley.

The Demise of Seventeenth Avenue is on display at the Glenbow Museum until May 22, 2016 as part of the exhibition Recent Acquisitions.