diff --git a/cairo_vm_hints/src/cairo_types/new_syscalls.rs b/cairo_vm_hints/src/cairo_types/new_syscalls.rs
index a60d7637..866abf88 100644
--- a/cairo_vm_hints/src/cairo_types/new_syscalls.rs
+++ b/cairo_vm_hints/src/cairo_types/new_syscalls.rs
@@ -1,5 +1,5 @@
 use crate::cairo_types::traits::CairoType;
-use cairo_type_derive::{CairoType, FieldOffsetGetters};
+use cairo_type_derive::FieldOffsetGetters;
 use cairo_vm::{
     types::relocatable::Relocatable,
     vm::{errors::memory_errors::MemoryError, vm_core::VirtualMachine},
@@ -7,20 +7,64 @@ use cairo_vm::{
 };
 
 #[allow(unused)]
-#[derive(FieldOffsetGetters, CairoType)]
+#[derive(FieldOffsetGetters, Debug)]
 pub struct CallContractRequest {
     // The address of the L2 contract to call.
     pub contract_address: Felt252,
     // The selector of the function to call.
     pub selector: Felt252,
     // The calldata.
-    pub calldata_start: Felt252,
-    pub calldata_end: Felt252,
+    pub calldata_start: Relocatable,
+    pub calldata_end: Relocatable,
+}
+
+impl CairoType for CallContractRequest {
+    fn from_memory(vm: &VirtualMachine, address: Relocatable) -> Result<Self, MemoryError> {
+        let contract_address = *vm.get_integer((address + 0)?)?;
+        let selector = *vm.get_integer((address + 1)?)?;
+        let calldata_start = vm.get_relocatable((address + 2)?)?;
+        let calldata_end = vm.get_relocatable((address + 3)?)?;
+        Ok(Self {
+            contract_address,
+            selector,
+            calldata_start,
+            calldata_end,
+        })
+    }
+    fn to_memory(&self, vm: &mut VirtualMachine, address: Relocatable) -> Result<(), MemoryError> {
+        vm.insert_value((address + 0)?, self.contract_address)?;
+        vm.insert_value((address + 1)?, self.selector)?;
+        vm.insert_value((address + 2)?, self.calldata_start)?;
+        vm.insert_value((address + 3)?, self.calldata_end)?;
+        Ok(())
+    }
+    fn n_fields() -> usize {
+        4
+    }
 }
 
 #[allow(unused)]
-#[derive(FieldOffsetGetters, CairoType)]
+#[derive(FieldOffsetGetters, Debug)]
 pub struct CallContractResponse {
-    pub retdata_start: Felt252,
-    pub retdata_end: Felt252,
+    pub retdata_start: Relocatable,
+    pub retdata_end: Relocatable,
+}
+
+impl CairoType for CallContractResponse {
+    fn from_memory(vm: &VirtualMachine, address: Relocatable) -> Result<Self, MemoryError> {
+        let retdata_start = vm.get_relocatable((address + 0)?)?;
+        let retdata_end = vm.get_relocatable((address + 1)?)?;
+        Ok(Self {
+            retdata_start,
+            retdata_end,
+        })
+    }
+    fn to_memory(&self, vm: &mut VirtualMachine, address: Relocatable) -> Result<(), MemoryError> {
+        vm.insert_value((address + 0)?, self.retdata_start)?;
+        vm.insert_value((address + 1)?, self.retdata_end)?;
+        Ok(())
+    }
+    fn n_fields() -> usize {
+        2
+    }
 }
diff --git a/cairo_vm_hints/src/syscall_handler/call_contract.rs b/cairo_vm_hints/src/syscall_handler/call_contract.rs
index fb49115d..f767105e 100644
--- a/cairo_vm_hints/src/syscall_handler/call_contract.rs
+++ b/cairo_vm_hints/src/syscall_handler/call_contract.rs
@@ -1,9 +1,13 @@
-use super::utils::{SyscallHandler, SyscallResult, WriteResponseResult};
+use super::utils::{SyscallExecutionError, SyscallHandler, SyscallResult, WriteResponseResult};
 use crate::cairo_types::{
     new_syscalls::{CallContractRequest, CallContractResponse},
     traits::CairoType,
 };
-use cairo_vm::{types::relocatable::Relocatable, vm::vm_core::VirtualMachine, Felt252};
+use cairo_vm::{
+    types::relocatable::{MaybeRelocatable, Relocatable},
+    vm::vm_core::VirtualMachine,
+    Felt252,
+};
 
 pub struct CallContractHandler;
 
@@ -17,10 +21,32 @@ impl SyscallHandler for CallContractHandler {
         Ok(ret)
     }
 
-    fn execute(_request: Self::Request, _vm: &mut VirtualMachine) -> SyscallResult<Self::Response> {
+    fn execute(request: Self::Request, vm: &mut VirtualMachine) -> SyscallResult<Self::Response> {
+        let _calldata: Vec<Felt252> = vm
+            .get_range(
+                request.calldata_start,
+                (request.calldata_end - request.calldata_start)?,
+            )
+            .into_iter()
+            .map(|f| f.and_then(|f| f.get_int()))
+            .collect::<Option<Vec<Felt252>>>()
+            .ok_or(SyscallExecutionError::InternalError(
+                "Memory error: failed to read full calldata"
+                    .to_string()
+                    .into(),
+            ))?;
+
+        // SYSCALL HANDLER LOGIC HERE!
+
+        let retdata = vm.add_temporary_segment();
+        let data = vec![
+            MaybeRelocatable::from(Felt252::TWO),
+            MaybeRelocatable::from(Felt252::THREE),
+        ];
+        vm.load_data(retdata, &data)?;
         Ok(Self::Response {
-            retdata_start: Felt252::from(0_u32),
-            retdata_end: Felt252::from(1_u32),
+            retdata_start: retdata,
+            retdata_end: (retdata + data.len())?,
         })
     }
 
diff --git a/cairo_vm_hints/src/syscall_handler/utils.rs b/cairo_vm_hints/src/syscall_handler/utils.rs
index 611ee905..c09f7791 100644
--- a/cairo_vm_hints/src/syscall_handler/utils.rs
+++ b/cairo_vm_hints/src/syscall_handler/utils.rs
@@ -212,8 +212,6 @@ fn write_failure(
     Ok(())
 }
 
-// Dummy value we dont use gas in HDP runtime
-pub const REMAINING_GAS: Felt252 = Felt252::from_hex_unchecked("0xffffff");
 pub const OUT_OF_GAS_ERROR: &str =
     "0x000000000000000000000000000000000000000000004f7574206f6620676173";
 
@@ -224,17 +222,17 @@ pub fn run_handler<SH>(
 where
     SH: SyscallHandler,
 {
+    let remaining_gas = felt_from_ptr(vm, syscall_ptr)?;
     let request = SH::read_request(vm, syscall_ptr)?;
     let syscall_result = SH::execute(request, vm);
     match syscall_result {
         Ok(response) => {
-            write_felt(vm, syscall_ptr, REMAINING_GAS)?;
-            // 0 to indicate success.
+            write_felt(vm, syscall_ptr, remaining_gas)?;
             write_felt(vm, syscall_ptr, Felt252::ZERO)?;
             SH::write_response(response, vm, syscall_ptr)?
         }
         Err(SyscallExecutionError::SyscallError { error_data: data }) => {
-            write_failure(REMAINING_GAS, data, vm, syscall_ptr)?;
+            write_failure(Felt252::ZERO, data, vm, syscall_ptr)?;
         }
         Err(error) => return Err(error.into()),
     };