Kourtney Kardashian's secret family heartbreak revealed as son Mason, 14, refuses to join her for two-week stay in Australia with her new husband Travis Barker

Kourtney Kardashian arrived in Sydney, Australia with her kids Penelope and Reign on this week's penultimate Season 5 episode of The Kardashians, but the mother of four has revealed the trip was tinged with sadness over her teenage son Mason.

She also brought her newborn child Rocky with on the two-week trip, as she followed husband Travis Barker through part of his band Blink-182's tour. 

‘I am in Australia, we made it. We’ve been having the best time. Travis is touring to different cities in Australia for about a week, but because I was on bedrest before, and then having a newborn at home, I haven’t really had any outings with my other kids, so really I wanted to stay in Sydney,’ Kourtney says in confession, as they show footage of Kourtney and the kids trying to play tennis… though Reign screams when the ball comes near him.

However, her oldest child, 14-year-old son Mason, didn't come, as she said in confession he, 'is home with his dad, which makes me really sad, but I’m making the most of every second,' with the episode coming after Kourtney celebrated Penelope's 12th birthday.

Last week's episode featured a brief part where Kim said she would try to convince Mason to go on the trip by telling him all the cool things Australia has to offer, though that didn't seem to work. 

Kourtney Kardashian has arrived in Sydney , Australia with her kids Penelope and Reign on this week's penultimate Season 5 episode of The Kardashians, though the mother of four is a bit sad

‘I am in Australia, we made it. We’ve been having the best time. Travis is touring to different cities in Australia for about a week'

However, her oldest child, 14-year-old son Mason, didn't come, as she said in confession he, 'is home with his dad, which makes me really sad, but I’m making the most of every second,' with the episode coming after Kourtney celebrated Penelope's 12th birthday

Reign is seen feeding a horse a carrot, as Kourtney asks Reign and Penelope their ‘peak and pit of Australia so far.’

Reign says, ‘My favorite part is the ice cream,’ as Kourtney admits, ‘The ice cream is delish,’ as Reign adds, ‘and that sucks for a favorite. My favorite is supposed to be going on a roller coaster,’ but Kourtney explains, ‘We’re going on one tomorrow,’ which makes Reign smile.

Penelope says, ‘Going to the beach and my pit was that there was like a shark attack so I don’t wanna go in the water.’

Reign dismisses her comment and says, ‘Eh, who cares, one person were gonna get bit, I’ll take the risk.’

The nanny Allie Garcia asks Kourtney what her peak and pit has been, as she responds, ‘My peak, probably hanging out at Miranda’s. I felt like I learned so much from her mom on like the traditions that I wanna keep in my house now with the kids, like how the mom is always cooking and taking care of everyone.’

Allie added that, ‘The son was so like helpful,’ as Kourtney added, ‘And like they all do the dishes together. My pit was the spider.’

They show footage of a rather large spider walking across a white wall, as Kourtney explains in confession, ‘So the only reason I could never move to Australia is for the spiders.’

Kourtney tells her kids and Allie, ‘I look for spiders everywhere,’ adding in confession, ‘It’s just terrifying and it’s just not the way I wanna live my life.’

Reign is seen feeding a horse a carrot, as Kourtney asks Reign and Penelope their ‘peak and pit of Australia so far.'

Reign says, ‘My favorite part is the ice cream,’ as Kourtney admits, ‘The ice cream is delish,’ as Reign adds, ‘and that sucks for a favorite. My favorite is supposed to be going on a roller coaster,’ but Kourtney explains, ‘We’re going on one tomorrow,’ which makes Reign smile

Penelope says, ‘Going to the beach and my pit was that there was like a shark attack so I don’t wanna go in the water'

Reign dismisses her comment and says, ‘Eh, who cares, one person were gonna get bit, I’ll take the risk'

The nanny Allie Garcia asks Kourtney what her peak and pit has been, as she responds, ‘My peak, probably hanging out at Miranda’s. I felt like I learned so much from her mom on like the traditions that I wanna keep in my house now with the kids, like how the mom is always cooking and taking care of everyone'

They show footage of a rather large spider walking across a white wall , as Kourtney explains in confession, ‘So the only reason I could never move to Australia is for the spiders'

They show footage of a rather large spider walking across a white wall, as Kourtney explains in confession, ‘So the only reason I could never move to Australia is for the spiders'

They leave the restaurant as Penelope says, ‘There’s paparazzi right there,’ as they show the photographer as Reign yells, ‘Hi paparazzi you stalker'

They notice the photographer has started running away as they walk the other way

Kourtney asks her kids, ‘Do we love Australia?’ Penelope nods yes and Reign says, ‘Sure,’ with an exaggerated wink.

Kourtney insists in confession, ‘I don’t know where he gets his sense of humor. He’s like a mini Jim Carrey.’

Back at the meal Reign looks into the camera and says, ‘So once upon a time…’ but then looks up at the ceiling, as Penelope crosses her arms, unimpressed, as Reign looks back down into the camera and says, ‘That was the story,’ and starts laughing, as Penelope insists, ‘It’s not that funny,’ as he gives her a strange look.

Kourtney admits in confession, ‘I’m starting to get a lot of vibes like his dad. I think he’s starting to get that sense of humor. I’m like, just what we need.’

They leave the restaurant as Penelope says, ‘There’s paparazzi right there,’ as they show the photographer as Reign yells, ‘Hi paparazzi you stalker.’

Kourtney says, ‘I don’t see us standing out here a long time if that guy’s here,’ as she adds in confession, ‘The paparazzi are everywhere in Sydney. Everywhere.’

They notice the photographer has started running away as they walk the other way, as Kourtney adds in confession, ‘Which is why I’m not taking Rocky out, but as much as I would love to stay home and be in my bubble, it’s not fair to have my kids all the way in Australia and not take them out to do things.’

They all head to a van as Kourtney tells them, ‘We can’t let them ruin our whole time,’ as the van drives away.